0 there in afghanistan. we continue our coverage right now. let's toss it over to garrett haake. garrett? >> chris jansing, thank you. i'm garrett haake. there has been an explosion outside the kabul airport. you're looking at live pictures of the airport. it's 6:30 in the evening tonight. pentagon says casualties are still unclear at this point. we know that the president has been briefed on the explosion. he was in a preplanned national security meeting this morning. white house officials are huddling as we speak. we hope to learn more from them soon. the airport has been under a terror threat all morning. this was going to our top story even before this attack. so, americans have been told to leave the airport gates and to stay away. all of this is happening as the pentagon is set to give an update in the next 30 minutes. we'll see if that remains on schedule and we'll bring it to you live when it happens. meantime we'll try to stay on top of this with our reporters. courtney kube is at the pentagon. geoff bennett remains at the white house. and sanchez is in london. what do we know so far, courtney? >> reporter: we know very little details. so far, this appears to be an explosion that occurred outside the airport at the abby gate. for perspective, the abby gate is over on the far southeast side of the airport. it's voupded by an area that was frequented by westerners. there's a hotel, baron hotel that a lot of westerners stayed up until the taliban took over the city a week ago. it's a place where there actually has been some movement of u.s. personnel, americans, some afghans going through there. the u.s. military marines and in some cases soldiers have actually been at that gate, letting people through. there's also been some u.s. consular affairs officers, state officials at that gate. this was a place where there was a lot of concern about a potential attack leading up to today. we've been hearing about it in the last several hours. this is a threat from isis. there was very specific intelligence that isis was look ing to target one of the gates at the airport, potentially to try to attack, kill americans, westerners, even afghan civilians. because of that, one of the real vulnerabilities that the u.s. saw was the large crowds that gathered outside the gates the last several days. they were worried some isis fighter would infiltrate those gates, someone with a suicide attack, suicide bomber or a vehicle-born improvised explosive device, someone who is able to get an explosion, a bomb inside a vehicle, drive it up, blow it up, kill civilians one of the big concerns, in addition to loss of life, is that they would breach the walls there and potentially people could get through. at this point these are the worst case scenarios that the u.s. was concerned about. we have no idea yet any reports of casualties. we don't know any vulnerabilities or anything that's been down to the perimeter of the airport. we're still trying to figure out exactly what happened here, what this explosion was. again for perspective, this was a place where there were american military stationed. this is where americans have been going through and afghans and other westerners as part of this evacuation mission, garrett? >> courtney, i'll let you work your sources a little bit and go around the horn. this is something like the countries in uk, australia, our nato allies, folks involved in afghanistan have been worried about as well. i understand there was some intelligence from the british side, concerned about exactly the type of attack that courtney was just describing. granted, we don't know exactly what happened here. again, there were concerns about this general type of explosion or attack could happen at the gates from the uk side. what more can you tell us about that? >> yeah, garrett, it is 3:00 p.m. here in london. all morning, the british government has been warning very, very urgently about what they have been calling the threat of a highly imminent, lethal attack on kabul airport. now these were not vague warnings. these were not general expressions of concern. this was senior members of the british government going on television and saying we are very concerned. there could be an explosion at the airport in the next couple of hours. so clearly, there is intelligence that the british government was aware of, that the u.s. government was aware of, presumably was shared more widely among the allies. as you say, we don't know exactly what has happened here, but the uk was certainly concerned about an attack at the airport. now, there are 1,000 british troops alongside american forces at kabul airport. some of them have been stationed at the abby gate that courtney was talking about, along the southern perimeter. we do not yet have any word from the british government of casualties either among afghan civilians gathering at that great or perhaps british troops in the area. we don't yet know what is going on, on that front. but the uk has been signaling that their evacuation is coming to an end. they cannot stay in the country without the support of u.s. troops. boris johnson tried, but did not succeed, earlier this week at that virtual g7 summit to convince president biden to extend his august 31 deadline for keeping u.s. troops in the country. today the prime minister said this phase of the evacuation is coming to an end pretty soon. we don't know exactly when. they will have to halt the process of flying out civilians and move the british focus to withdrawing uk forces. the prime minister is trying to look beyond that point, saying we will continue a diplomatic and political effort to pressure the taliban to continue to let afghans out, even after western forces are gone. but, garrett, this explosion at the airport today will complicate what was already a very, very delicate situation on the ground in kabul. >> yes, it will, almost regardless of what happened there. i understand the british armed forces minister spoke about this threat a little earlier today prior to this taking place. i want to play a little bit of what they had to say. >> intelligence over the course of the week has become ever more certain around the highly credible, imminent, lethal attack on to the airport whilst, of course, the clock is still ticking toward the end of the month. we have to share that very, very real threat with people in kabul and advise them that they should move away from the airport, not come to the airport. >> and now geoff bennett at the white house. obviously this is the kind of information the u.s. government has as well. there's warnings from the state department to americans who might have still been in kabul overnight. talk to me about how the white house is responding to this. i mentioned at the top the president was already scheduled to have a meeting about afghanistan this morning as we were finding out about this. >> that's right, garrett. look, this scenario is certainly what this administration had feared and also what this white house had warned about, national security adviser, jake sullivan, telling us reporters in the briefing room last week that the threat in afghanistan posed by terror organizations was real and acute. president biden, in his remarks before the nation days ago, saying u.s. troops in the region, coalition forces in the region face a grave and growing threat the longer they stay there. as you see, a live picture there of the airport, i can sort of bring you up to speed on the state of play of evacuations. this explosion has happened as the window of evacuations is closing rapidly. the pentagon had already acknowledged that as we reached this august 31st deadline, space -- available space will be reserved for troops to make sure they are safely out of country by august 31st. we heard from the state department yesterday there are roughly 1,500 americans believed to be remaining in afghanistan. we heard secretary blinken say that the state department has contacts for about 500 of those americans, that they are actively reaching out to them, trying to bring them safely to the airport. there are believed to be roughly 1,000 americans for whom the administration is frantically trying to contact. there are outside estimates that there are some 250,000 afghans who have worked alongside the u.s. mission over the last 20 years who would be eligible for the expedited visas. most of those folks will have to remain in country after august 31st. you also heard secretary blinken say they will spare no resource, economic, diplomatic, working with allies, the u.s. working with its allies to try to grant safe passage to any afghan, any american who remains in country after august 31st. this explosion, presumed attack outside the kabul airport, you can certainly imagine how that complicates this effort and the immediate political calculus that president biden has to make here. >> geoff bennett, thank you. as we're watching aircraft still taking off from the hamid karzai international airport at kabul, we should be clear what we know and what we don't know. we know there was an explosion of some kind outside the abby gate at the airport here in afghanistan. somewhere around 6:00 local time there. we've been following reports of this at least for the last 20 or 30 minutes or so. we've been getting bits of information here. we know that this is something that u.s., uk intelligence were aware of coming into this, the possibility that there could be some kind of terror attack here. and we know that the security situation on the ground has been a case of strange bedfellows with the united states and taliban trying to work to secure the various gates to this airport while the u.s. was completing this air lift. rob sanchez, you're in london. let's talk a little bit about the players on the ground here. because the threat here, unusually for americans who follow this war in afghanistan the last 20 years, wasn't from the taliban. they were effectively security partners now. there's been a lot of talk about isis-k, the isis affiliate in central asia. what do we know about that group and the concern that these allied intelligence agencies might have had about them trying to make a splash while the u.s. is still in afghanistan? >> reporter: yeah, garret. so isis-k is isis khorasan. khorasan refers to an area of central asia. this is the afghan affiliate of the islamic state. it has not attracted the kind of international attention that so-called main isis in syria and iraq has captured. the trump administration did drop a massive ordinance bomb, a bomb that is basically just one level below a nuclear weapon, on this group's facilities in afghanistan a couple of years ago. there were questions at the time to what extent the use of that bomb was actually a legitimate battlefield tactic and to what extent the trump administration was just trying to make a show. but isis-k has been around for a number of years. we are used to referring to the taliban as an extremist group. they are. these isis members are far more extreme than the taliban. and, as you say, they are looking to make a splash. they are looking not only to harm americans on the way out of the country, but they are also looking to embarrass this new taliban regime, who they see, if you can believe it, as sort of collaborators with the united states. they see armed taliban forces standing just a few yards from american troops around the perimeter of kabul airport, and they see this as a form of tr c hary. this is one of the major issues they'll find themselves contending with, a small but highly lethal, highly fanatical group of people committed to fighting them as well as the americans. garrett? >> geoff, obviously, this is the kind of thing we've been talking about in a diplomatic context the next couple of days. what will the taliban look like as a government? what will their approach be to terrorism or isis or al qaeda operating within their country? with the caveat we don't know all that we don't know here, beyond the fact that there has been this explosion outside the airport? how do we expect the u.s. government, the state department, those contacts we've been hearing about on a tactical level between commanders on the ground in afghanistan, or the white house to coordinate with the governing authority in afghanistan that is now the taliban to deal with these kinds of situations? >> reporter: it's a great question, garrett, for which i don't specifically have a good answer. we do know that the taliban has been a bewildering and baffling partner in all of this. given that up until, you could say, two or three weeks ago, they were an adversary that the u.s. was intent on trying to eradicate. now we are heavily reliant, in some cases entirely reliant on the taliban granting safe passage to those americans and qualifying afghans to the airport owe that they can be evacuated. to the degree that this explosion changes that relationship and changes that tower balance, that remains to be seen. we are still waiting to learn more about who is responsible, who or what group is responsible for this attack and the number and nature of the casualties, if there are any. but, yes, it certainly is one of the many decision points and one of the many areas of influence and questions that remain that president biden will certainly have to take as he makes decisions and the next steps here. >> let's focus on what we do know. the pace of evacuations from this airport has picked up substantially in the last couple of days. administration officials from the pentagon, the white house, to the state department have been very pleased with what they have seen of the air lift over the last couple of days. help set the scene for me now as we come into thursday night in kabul, where the u.s. is on pace to finish what has been this massive air lift operation. something like 100,000 people moved since kabul fell. where are they in this effort? we've been watching some planes take off here from kabul, and how much work does the administration believe they still have left to do in the time that remains ahead of that deadline? >> reporter: the largest-known air lift in u.s. military history, as you mentioned, nearly 100,000 people since august 14th, since this air lift process started. we got more clarity on where we are in this mission yesterday from the state department. as i mentioned, you heard secretary blinken say they put a firm number, as firm as he could possibly put on the number of known americans remaining in the country, 500 merps for whom they have contact, reaching out phone, email, anywhere they can, for those americans who do want to leave, to try to get them to the airport as quickly and safely as possible. and then there is this larger number, roughly 1,000 americans that they believe to be remaining in country. the reason they can't put a hard number on that is because we heard from secretary blinken yesterday say when americans travel overseas, the u.s. doesn't track them. it is entirely up to americans to register with the embassy when they arrive and leave. lots of folks don't do that. there might be americans who want to remain in country. up until this point, up approximate until about an hour ago when we got the breaking news of this explosion, that had been the primary focus of this administration, getting their arms around the specific number of americans who remain am country. president biden said that was his primary focus, making sure any americans who wanted to be air lifted out could be and beyond that the hundreds of thousands of afghan allies, folks who worked as interpreter, translators, staff at the various airports and military bases and embassies, making sure that they and their families were also granted safe passage. this explosion certainly upset a lot of that. and a lot of that decision making and certainly figuring out in the process of winding down this operation what comes next, garrett. >> watching, i think, the third or fourth flight we've seen take off since we've come on the air in this hour. we know at least some traffic in that air lift is still moving from the hamid karzai airport in afghanistan. raf, i want to bring you back in. you touched on this earlier but this entire war effort has been a coalition effort with our nato allies playing a huge part. we talked a great deal in the united states about the american forces drawing down over the next few days. what's the state of play among our other allies who are remain ing? i saw something this morning about the dutch ending their continued presence in afghanistan. what remains of the uk footprint? kind of who is left here to finish the job? >> reporter: yeah, garrett, that's exactly right. one by one by one, america's european and other allies are signaling their evacuations are coming to an end. the last canadian flight was happening today. last flight of civilians. we are expecting a relatively small number of canadian troops to be evacuated next. as i said, there's about 1,000 uk troops who are there, alongside u.s. soldiers, u.s. marines, manning the perimeter of this airport. the uk has had the second largest number of western forces in afghanistan after the united states. they have suffered the second largest number of casualties. there has been a lot of attention here that, you know, this 20-year war effort that britain has been involved in, beginning with tony blair, standing alongside george w. bush immediately after the september 11th attacks, and ending now under boris johnson's premiership, there's been a sense that this war is coming to a fairly chaotic end. we've heard relatively unusual public criticism from british officials of how the u.s. has handled this. the british defense secretary is a former soldier. he actually got emotional during an interview last week, saying that it was pretty much inevitable that afghan allies of the uk were going to get left behind in kabul because of this timeline set by president biden. there has not been the same level, i would say, of political interest here in britain that there has been in the u.s. about the war in afghanistan. there's not much discussion about forever wars in this country in the way there is in the u.s. but the uk has suffered fewer casualties than the u.s. has. it has spent less blood, less treasure. but still it is something that is being very closely followed here in the uk, especially as british forces remain on the ground. garrett? >> geoff, i keep thinking this attack is a pretty good example of being pre of the united states, you don't get to choose which crises you're forced to deal with. the president's critics, some in his own party, would say he has choech this outcome, this kind of evacuation, this kind of ending in afghanistan. the prime minister of israel is set to visit today, major foreign leader visit. now the president most certainly will be dealing with this in some way. talk about how the white house is continuing to juggle this massive foreign effort here in afghanistan, this massive air lift with, oh, by the way, really big and important week on their domestic front in washington, too. and the way they'll have to juggle this foreign leader visit, the challenges set before this president in august when it's supposed to be sleepy, but it almost never is when it comes to the crises that the president of the united states has to deal with. >> reporter: great point. the president is meeting with the israeli prime minister. there's no known changes to the president's schedule today. yes, garrett, you can almost imagine the voices that will say that this process, this evacuation process should have started earlier to sort of avoid the situation that unfolding this morning. president biden, white house officials have been consistent in saying well beyond -- to be clear well beyond, before this attack happened, that a