election offices are targeted with suspicious letters. more than a dozen have been sent across the country. one confirmed to be laced with fentanyl. the latest on the federal investigation and whether officials believe these letters are connected just ahead. also, wherever you go, it seems that screen is flipped around, and you're faced with pressing math questions. has tipping gone too far? new polling ahead. we're following these major developing stories and many more all coming in right here to "cnn news central." israel's war on hamas intensifying on the streets of gaza. before we show you some new footage, we want to warn you some of these images are disturbing. this new video shows people trapped under rubble. buildings collapsed by israeli barrages on thursday, victims being pulled out of the rubble in a desperate search for survivors. today gunfire sent palestinian civilians near one hospital in northern gaza scrambling for safety. it comes amid reports that israeli air strikes have damaged several hospitals. the head of al nassar hospital says israeli tanks have surrounded his facilities. keep in mind, the idf has maintained it exclusively targets areas with ties to hamas, and that any civilian losses are unintended. according to the palestinian ministry of health, which draws its figures from the hamas-controlled territory, 11,000 palestinians have died since october 7th. meantime, thousands more fled gaza -- fled south toward -- fled south in gaza today. as israeli forces opened a six-hour evacuation corridor. there are growing international demands to further address the dire humanitarian crisis. all of this is unfolding. speak after meetings in india, the secretary of state antony blinken gave one of his most direct condemnations yet of the mounting death toll. watch this. >> much more needs to be done to protect civilians and to make sure that humanitarian assistance reaches them. far too many palestinians have been killed. far too many have suffered these past weeks. >> cnn's nic robertson is live in sderot, israel. the damage to these hospitals is concerning. what can you tell us about the circumstances surrounding these attacks? >> reporter: yeah, the international committee for the red cross says that the state of the hospitals and health care system in gaza now has reached a point of no return. the figures that are being released by the hamas-controlled ministry of information say, for example, 198 health care workers have been killed. and while israel is surrounding it appears several hospitals in gaza at the moment because it believes they're connected to hamas operations, they say that under some of those hospitals there are bunker and tunnel networks belonging to hamas. health officials at those hospitals deny any knowledge of those systems, saying they don't exist. the health care system in gaza, when you look at the humanitarian situation, does seem to be by the statistics that are given by, again, the hamas-led health authority there, dire. 21 of 35 hospitals are now out of service. 51 of 72 health care clinics are now out of service. so the humanitarian situation while the corridor has been open and perhaps open for its longest period today and many thousands of people were seen fleeing the north of gaza to the south of gaza to clear the area in the north that the edf calls a battlefield zone, the toll that it's taking on the infrastructure and the ability of people in gaza to be able to treat themselves is escalating. it mounts day by day by day. the idf say they have now targeted 15,000 different terror sites. they've rounded up so far 6,000 different weapons. they've discovered hamas weapons-making facilities inside domestic homes right next to the bedrooms of children. there are tunnel networks that have been demolished and destroyed indeed. tonight as i stand here, i can still hear the detonations and explosions continuing to come from gaza as they have done throughout the day. so the military operation continues. the humanitarian operation continues. the dire medical situation like so much else in gaza seems to be getting worse. >> nic robertson live from sderot. thank you so much. at the same time cnn is learning that american diplomats are warning the biden administration of growing fury in the arab world against the u.s. for its strong support of israel's deadly military campaign in gaza. we have cnn's natasha bertrand here with more. cnn has obtained this diplomatic cable that spells out the concern. what does it say? >> reporter: this cable was obtained by our colleague priscilla alvarez, written by the second highest official in the embassy in oman. what it does is -- it's essentially a warning based on conversations that they're having with people in the region about how the arab world is looking at the u.s.' ongoing support for israel amid this massive bombardment of gaza. what it says is that -- it warns the white house, the fbi, and the cia that the u.s. is losing u.s.-arab publics for a generation, it says, and says that u.s. support for israel is being seen as, quote, material and moral culpability in what they consider to be possible war crimes. now this is a message that has been communicated directly to the secretary of state, to the u.s. administration by the u.s.' arab partners including jordan, egypt, all people that -- all countries that the secretary of state met with in the last few weeks to try to discuss the path forward here. and what those arab countries are asking for is a cease-fire. they say they want to see the fighting stopped completely. they want to see palestinian civilians be able to get out of gaza. of course, the u.s. has stopped short of that. they are not supporting a cease-fire at this point. instead what they're saying is they support these temporary pauses, and they are pushing for a three-day pause. president biden said he wants it to be even longer than that. right now that seeps to be the contours of the deal that is taking shape in order to allow not only civilians to get out but also hostages. but look, this is -- this is really what the administration is grappling with. they are having to toe this delicate line between supporting israel and its right to defend itself against the hamas attack, but also calibrating that in a way that expressions that they do -- expresses the that they do not support the way israel is carrying out the campaign. >> the civilian deaths, they may say they're unintentional but they're astronomical as we look at them. thank you so much. boris? let's dig deeper on all of this now. joining us is cnn national security analyst and former deputy director of national intelligence, beth sanner. also, a former spokesperson for the u.s. mission to the united nations. she's also the former director for syria and lebanon on the national security council. ladies, thank you both for sharing part of your afternoon with us. hagar, to you, the secretary of state one month ago said that u.s. support for israel is ironclad. that to me seems different than what we heard today when he said, quote, too many palestinians have died. do you think it's fair to say that the scenes coming out of gaza have forced the u.s. to shift its tone? >> well, not entirely because israel has been a non-nato ally since 1987. so that support is ironclad for many reasons. it's a relationship that is both give and take. we both mutually benefit from that relationship. that doesn't mean as you have with any kind of ally, by the way, we have many allies all over the world where we've had to have difficult conversations or press on certain issues or use the leverage that we have and with israel, for example, obviously u.s. leverage does weigh heavily. it doesn't always work, but it does weigh heavily. and so that doesn't mean that we're not able to use that leverage because either there's a national security objective that we want to achieve, or in this case in particular, believe that a high civilian death toll undermines israel's broader cause of a more secure israel. and that is the u.s. view. so i wouldn't view it as fraying at the relationship or anything like that. a shift in public messaging or -- and private messaging is to be expected even when it's an ally. >> beth, he also said much more needs to be done to protect civilians. this is one day after the white house announced that israel had formalized plans for these hours' long pauses in fighting. but the u.n. human rights chief expressed doubt as to how effective these safe zones are. are they effective? what more do you think should be d done? >> i think that there's a gap between our rhetoric and what people are seeing on the ground. and that's not necessarily our fault. i mean, there's only so much we can do in terms of trying to persuade and pressure israel on these matters. but you know, i think that that's the problem is that, you know, the arab populations do see us as not actually delivering on our promises. i would say that one thing that we could absolutely do is maybe turn our eyes and be more direct about what is happening in the west bank. we have to look ahead. what is happening in the west bank with the extremist settlers that are being supported by the idf in many, many instances, were a blind eye in other cases, but palestinians are being pushed out of their homes. if we really actually want to support a two-state solution, we have to insist that this stop. so there are things that are happening that we could actually make a difference on in gaza and in the west bank. we have to do a better job. >> the question of the extremist settlers is something the secretary of state said he would bring up multiple times with prime minister netanyahu. beth, staying with something that you mentioned about perception across the region and the arab world, your reaction to this cable, this diplomatic cable that effectively says the u.s. is losing a generation diplomatically. >> well, yes and no. i feel that in some ways we've already lost the youth generation in the arab countries. i mean, very reputable polls or barometer shows 15%, 1-5 percent of palestinians view the united states favorably, and that is because over the past five or six years in particular we haven't been able to make progress on a two-state solution. part of that is because the israelis don't want to make progress on that. at least the governments in charge. but you know, across the arab world, fewer than majorities support the united nations. and when you look at the -- the united states. and when you look at the youth, one poll that says over 50% of arab youth see the united states as an enemy. that poll was taken a year ago. so we have a problem here. we talk about -- we heard president biden talk about the united states being the light on the hill, the beacon of hope. but we have to recognize that part of that is mythology. and we have to work harder as a country if we really want to be that. >> hagar, simultaneously, you have u.s. forces in the region, they've been targeted at least four times since u.s. air strikes in syria on wednesday. how long do you think these attacks can continue against the u.s. before the u.s. military finds itself more involved in this war, worsening the situation that beth described? >> sure. i have a saying that when the storms gather in the middle east it storms everywhere. that's usually because when you have instability in one certain region, especially if the u.s. is involved in some way, you're going to have other nefarious actors, iran-backed groups, terrorist groups try to take advantage of that situation and pursue whatever kind of goals or attacks they want -- they're going to try. in this case you've got, like you said, attacks against u.s. bases in the region. and i expect that to continue. and it's something that the u.s. expected, as well. it's something that while i'm not trying to diminish at all the threat, it is unfortunately something that the u.s. government is used to and generally prepared for. now that could escalate further which is why the u.s.-based military assets, additional military assets, these aircraft carrier groups in the mediterranean, in the red sea, and in the buffalo, and they have already -- the gulf, and nay have already been useful in intercepting actual rockets, you've had rockets they intercepted from iran-backed houthi militants against israel, and you also have their ability to kind of use -- to be used as a deterrent and to prevent things from escalating further. at the end of the day based on how iran is behaving, and their rhetoric where they have threatened to act when israel invaded gaza, while they've already invaded gaza, and hezbollah's rhetoric, from what it appears it appears also that, number one, iran doesn't want a full-scale war. they would prefer their proxies handle it for them. not all the proxies are involved. the houthis are, hamas is, perhaps some cells in the west bank. but hezbollah doesn't actually seem that interested in an -- in a full-scale war. and i think that that will be a continuing theme for the next few months or as violence continues in gaza where you're going to have these actors take advantage in these limited strikes and clashes, but that i don't expect it to unravel into something more major. >> to your point about hezbollah not wanting a full-scale war, we have seen more cross-border skirmishes between hezbollah and idf troops around israel's border with lebanon. and beth, i'm wondering if you think hezbollah is hesitant to go further partly because of what they've seen in gaza, or do you think they would be emboldened, perhaps, to take a more aggressive approach if israel then reduces some of its -- if it slows its attacks in gaza. >> i think that hezbollah right now, nazralah made a clear speech that he doesn't want this full-scale war, right. but he has to show his -- basically his base and the whole arab community that hezbollah, which is seen as the anchor of the access of resistance, that that's what they are. so they have to have these cross-border firings and, you know, continue this pressure on israel in order to show that they're doing that. whether they want to take advantage of that down the road, i agree completely that -- i don't think they do right now, i think the question really depends on, you know, what happens on the ground in gaza, does it -- is it going to get worse. if it gets -- if the israelis tune it back, yeah, i think eventually it will slow down. but if it ratchets it up, hezbollah will probably have to do more. and the real danger there is just whether thins get out of control. not that they intend to do something perhaps, but whether it gets out of control. at some point, you know, maybe rationality goes by the suiways, as well. i agree at this point it's not at the front burner. >> hagar, last question to you. is there a sense that the u.s. may soon have to expand its presence in the region? has the presence there been effective so far, some 60 u.s. service members have already been injured. >> yes. the one thing that i don't expect the u.s. to do is to limit its presence or back down in any way or remove troops because it would send the wrong message. it would send this message that this type of behavior, violence, terrorist attacks, militant attacks against bases and so on, that it would work. that it would push u.s. out of the region. that is exactly what iran and these iran-backed militants want. so that's the last thing i expect them to do on that part. whether they increase, i could see additional military assets in the waters, right, in the mediterranean sea, in the red sea, and in the gulf for sure. that is -- that's not new for the u.s. any time there have been tensions that increase in the region, whether they've been in the gulf or lebanon, so on, you often see carrier strike groups go to the area to try and send this message to show support for whomever it might be, in this case obviously israel, and for our own bases. and to send a strong message of deterrence. you've heard that over and over again from president biden, from secretary of defense austin, where they said if you even think about doing something, don't. i would take that as a very credible threat coming from the united states. it would take a lot for the u.s. to get involved in an actual war, by the way, even though israel is a non-nato ally, it doesn't necessarily mean that the u.s. would send troops into a war. i don't see that scenario playing out anyway. >> thank you both so much for the time. >> thank you. >> of course. still to come on "cnn news central," donald trump is infamous for giving his rivals unflattering nicknames. now president biden is trying one out on him. we'll explain. plus, from west virginia to the white house? democratic senator joe manchin says he is not running for re-election, so does that mean he's running for an even higher office? and later, a long journey home. how the three giant jet black pandas are doing after their fly from here in d.c. all the way to china. we'll be right back. vice president kamala harris making it official today -- filing paperwork to put joe biden on the 2024 presidential ballot in south carolina. that state will lead off the democratic primary, and it's part of the reason that joe biden won the nomination in 2020. it comes as the president takes a victory lap over elections this week and as he takes a job at the presumptive republican nominee donald trump. biden saying at a fundraiser, quote, we haven't stopped winning, and he hasn't stopped losing. the truth is the guy can't get tired of losing. biden also downplayed the cnn and "new york times" polls that show him trailing trump in a hypothetical rematch. let's discuss with jeff zeleny. what else did he have to say about the polls? >> it feels like general election time. we're not there yet. what president biden is clearly trying to do is show a little muscle and a little aggression here, going directly after the former president who's his likely opponent, but we don't know that yet. the republican primary hasn't started. he drilled down into these tuesday night election defeats in virginia. in a -- kentucky obviously and in ohio. he was talking about the jobs record under the former president, as well. he kind of coined a bit of a new nickname. he called him donald hoover trump, referring to president hoover who was presiding in office during the great depression, never mind the pandemic, i'm not sure that is going to stick. it reality is this is what president biden is trying to do. he's trying to remind people there's a choice, he won't be running alone. they're trying to make this a referendum, not a choice between -- between him and trump, not a referendum on his presidency. the bottom line this all this is the white house is on its heels a little bit after all these bad poll numbers. they're just trying to muscle up a little bit. but the -- in south carolina today, that's really what they would like to remember. those were some heady days when he won the primary there after some rough weeks. so when you talk to biden advisers they say don't count him out. there's a long time between now and november. they're trying to say this isn't a referendum on biden, it's a choice between biden and trump should it get there. >> the biden administration campaign didn't look great after -- >> fourth and fifth place. >> hoover trump. i'm not sure that's going to stick. >> a vacuum cleaner? no, the president, great depression. >> not the most effective insult for a guy trying to seem younger than he is. thank you so much. it has been less than 24 hours since democratic senator joe manchin said he is not seeking re-election. but inquiring minds want to know will he run perhaps for something else. his plans to travel the nation and mobilize the middle, that sound lik