Current intelligence that suggests a threat in these American Cities from washington, d. C. To chicago to los angeles, authorities are increasing security and deploying extra officers. We hope that the powers that be are doing what they need to do. Reporter security is not just beefed up on subways, but airports are also on high alert and bringing in additional armed patrols and canine units. Linsey davis, abc news, new york. As she mentioned air travelers can spec to see increased security. In orlando, a jet from brussels was isolated when it landed all this in the anxiety right after the terror attacks. Even with the extra security terminals are still considered soft targets. We will have clearly entered a period of new normal where we have to be concerned about a much broader range of attacks. The airport in brussells is expected closed until further notice. You know, the state department is warning terrorists may attack sporting events overseas but here at home, the final four facilities are two weeks in houston. After the brussels attacks security will be even tighter. City police will be getting help from state and federal agencies. This will be the largest ncaa mens Basketball Championship crowd ever. With the other final four activities, houston expects visitors. And ice is threatening other countries which take part in the u. S. Led military coalition. The terror group promises dark days for countries aligned against the Islamic State threatening what they say is coming is worse and more bitter. How is the war against isis being waged . Heres abcs martha raddatz. Reporter the air strikes have been constant. From the sea, from the land. Were out here to take out isis so it doesnt matter where theyre at. Were going to eliminate that threat. Reporter Surveillance Drones and cold war era spy planes patrolling the skies to help locate targets. The ground war, too, has been more effective. But there are estimates that 30,000 isis fighters are still spread throughout the region. Have a safe flight. Reporter we tacked one Night Mission from start to finish board the usa truman. F18s flying over syria to destroy an oil pipeline, a Revenue Source for isis. Three, two, one. A refueling mission midair over stormy skies and hostile skies. Lightning striking all around. Three, two, one. Reporter we met with the pilots on the flight line seconds after returning safely to the deck. It was not exactly routine. But we got the results we wanted. Reporter the u. S. Says intelligence has improved in the military fight, especially with more u. S. Troops backing up iraqi troops. And while the pentagon says that isis is weaker and on the defensive, the pentagon is the first to say that defeating isis will take more than military might. And our coverage on the brussels attack doesnt end here. Coming up, the tributes to the victims and how the city is coping with grief. Thats later this half hour. Were also tracking primary and caucus results come in right now from utah, idaho and arizona. Ted cruz has won the utah republican caucuses. Donald trump likely coming in third there. Those results just coming in. Republicans in arizona have given a landslide victory to donald trump who gets all of the states 58 did hes. As for the delegates in that state, they give Hillary Clinton the win who also adds to her delegate lead over Bernie Sanders. But sanders doesnt end the night empty handed. Handily winning with the utah and idaho democratic caucuses. Coming up right here, were going to return to our top story and how brussells is showing strength while coping with this grief. Also ahead, criticism for president obama going to a baseball game in cuba after at brussels terror attacks. What was his explanation and was and later, apple security showdown over a dead terrorist locked iphone. The developments from the fbi and concerns about privacy. ugh. does your carpet ever feel rough and dirty . Dont avoid it, resolve it. Our formula with a special conditioning ingredient, softens your carpet with every use. Its resolve, so you know it cleans and freshens. But it also softens. Resolve. A carpet that welcomes you. And to clean pet messes, try resolve pet expert. sounds of birds whistling introducing new ky touch gel cr me. For massage and intimacy. Every touch, gently intensified. A little touch is all it takes. Ky touch. Olay regenerist renews from within. Plumping surface cells for a dramatic transformation without the need for fillers. Your concert tee might show your age. Your skin never will. Olay regenerist, and try the microsculpting cream you love now with lightweight spf 30. Janet . Cough if you can hear me. Dont even think about it. I took mucinex dm for my phlegmy cough. Yeah. But what about mike . It works on his cough too. Cough it works on his cough too. Mucinex dm relieves wet and dry coughs for 12 hours. Lets end this. Germs . Disinfect your bathroom with lysol bathroom trigger. Lysol power foamer. And lysol toilet bowl cleaner. They kill 99. 9 of germs to clean and disinfect in and out of the toilet. Welcome back. Some other headlines now. A utility worker is dead after a construction accident in southern california. He was crushed between a crane and a trailer. Accident occurred near an area thats seen a construction and redevelopment boom in recent years. And we have a health alert this morning involving prescription pain killers. The fda planning to add a boxed warning to all Immediate Release painkillers including more than drugs, many of them oxycontin based. Its meant to fight opiate addiction often blamed for the growing heroin epidemic. New guidelines for prescribing the drugs were announced a week ago. Fresh supplies heading to the International Space station following a launch ive cargo rocket from Cape Canaveral in the light of a nearly full moon packed with 8,000 pounds of food, equipment and Scientific Research for nasa. It is due at the space station on saturdays the. It was a beautiful nighttime launch about 11 00 last night east coast time. Very nice. After a historic visit to cuba, president obama moves to the next nation on his itinerary. Argentina. Air force one landed in south america with the first family preparing to spend the day in the capital city of buenos aires. As Serena Marshall reports, his stop in cuba is still very much the focus. Final day in havana, markds by far away disaster. The look of horror as he learned about the brussels attack. Hours later addressing the cuban people but only a brief mention of the bombing. The thoughts and the prayers of the American People are with the people of belgium. Reporter before continuing his cuban push. I have come here to bury the last remnant of the cold war in the americas. Reporter the president pleating with dissidents and using baseball diplomacy as the two leaders watched, joked and took in the baseball traditions, obama telling espn why he didnt go home immediately as political rivals suggested. On a day marked by tragedy watching the game was so important. What they can doing is scare and make people afraid and disrupt our daily lives and divide us. And as long as we dont allow that to happen, were going to be okay. Reporter ending his day in cuba with castro seeing him off. Continuing on to argentina, the next two days with newly elected president Mauricio Macri macri. The trip will also include a first family visit to patagonia possibly taking in one of their famous glaciers. Unlike his visit in havana, in argentina he can expect a more controversial welcome. More than 10,000 people expected to come out and protest. His visit coming on the 40th anniversary of the military coup known as the dirty war. Serena marshall, abc news, havana. President obama at that baseball game was talking about one of his proudest moments in office was when boston united following the attacks there. He pointed specifically to red Sox David Ortiz for saying they wont be intimidated. Hes getting a lot of heat for going to the game. I distinctly remember in the days following 9 11 president bush was saying go on with your lives, go to disney world. Spend money. Do not let them disrupt our broadway opening up shortly after the attacks to send a message to say they will not have this one over people. There was a moment of silence at the game and there will be on capitol hill today. A lot of people remembering what is going on in belgium. Coming up, terrorists and technology. The battle to track suspects electronically is getting even more difficult. Thats next on world news now. Tt2w`t o mt; bt qyrl tt2w`t o mt; a qi tt2w`t o mt; bm qbu tt4w`t o mt; dztq o4 tt4w`t o mt; entq xkt tt4w`t o mt; gzt al, tt4w`t o mt; hnt qb tt4w`t o mt; iztq ; 8 tt4w`t o mt; jntq [x welcome back. As investigators dig deep into how the brussels terror attacks were coordinated a new turn in apple is refusing to help the government as it tries to unlock a terrorist iphone as you know. Only now the government says they might not need the help after all. Heres abcs neal karlinksky. The hunt is on to dissect every moment of these three possible terror suspects lives a search that will run straight through their cell phones as Law Enforcement struggles to uncover their digital footprints. Investigators faced the same challenge last year in paris uncovering a huge stash of disposable cell phones can activated one day before the attacks. Investigators continue to struggle to unravel the iphone used by said farouk. The Justice Department says it may not need apple at all. And telling a judge an outside party demonstrated to the fbi this past weekend a possible method for unlocking the phone. Apple has fought the it to weaken iphone security so investigators can break in. We have a responsibility to help you protect your data and protect your privacy. But its not just apple. There are a number of encrypted third Party Messaging Apps known to be used by terrorist and Law Enforcement worldwide is struggling to keep pace. Neal karlinksky, abc news, cupertino, california. Big mystery who was that third party. That is the big mystery. Apple so far sound a little skeptical of lou the third party will break into it. There was a Conference Call on monday. They were saying the Company Wants more information about the method used to break that iphone. I dont think they quite believe it is possible. My iphone did break over the weekend. Cracked in the middle. Not somebody hacking into it. No, but cracking is devastating enough. Okay. All right. Got to get that fixed today. There is that first world coming up, the world rallying around brussells. Look at these i cans all over world. Remembering brussels and belgium. My son and i used to watch the red carpet shows on tv now, im walking them. Life is unpredictable one thing i need to be predictable is to be flake free. Because i have used head and shoulders for 20 years. Used regularly, it removes up to 100 of flakes keeping you protected every week, every month, every year you ready ma . Always life is unpredictable, so embrace it head and shoulders. Live flake free for life everyone loves how they feel in dark clothes. And to keep those darks from fading. Theres woolite darks. Its free of harsh ingredients, keeping dark clothes looking like new for 30 washes so your love for dark clothes will never fade. Woolite darks. Janet . 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A temporary tribute 0 lives gone forever. And in cuba, president barack obama calling for global solidarity. This is yet another reminder that the world must unite. We must be together. Regardless of nationality or race or faith in fighting against the scourge of terrorism. Reporter in our nations capital, the American Flag lowered to halfstaff. All sing it with me, all right . With the rain blowing in your face in london adele offering this moving tribute to the victims performing make you feel my love in their honor. And in france, a cartoonist for lemomnd with a simple message. Together in a somber similarity. Pray for belgium shared all over the world in support. Millions heard the voices of those who lived through the harrowing hours. I can still feel the first blast. Recounting the horrific moments when survival was uncertain. It was the Worst Nightmare you could imagine. Reporter but perhaps more importantly, the true nature of human at this time that can shine bright even in the darkest times. It was really the sense of humanity that emerged in the sense of chaos to me shows that these types of things dont defeat the human spirit. So true. After the terror so often, you see incredible heartwarming stories thinking about the airport worker who reportedly pulled seven people to safety. How across the World Leaders have come together to show their solidarity. It was just about 24 hours ago that terror rained down on this morning on world news now, the search in brussels for an isis bomber. From the manhunt to the human toll to the travellers who feel vulnerable worldwide. Live coverage coming up. Terror investigation. Who were the men responsible for the brussels bombs . New details about their isis network. And which targets could be next. Paying tribute showing strength in brussels with heartfelt memorials to the victims. The city in grief trying to heal. And our other major story, long lines at polling places in three states. The candidates talk terrorism while donald trump and Hillary Clinton have an eye on the delegate counts. Its wednesday, march 23rd. World news now. Good morning, everybody. On this wednesday, im kendis gibson. And im reena ninan. The world is really grieving all that took place just about 24 hours ago. Want to show you a live picture right now of the empire state building. Youll note it is noticeably dark. They turned the lights off overnight in memory of the victims in belgium. And the president has announced that the white house, federal buildings, even military posts will all fly the flag at halfstaff until saturday night to honor the victims. So many people remembering the victims over there. We want to get to the latest coming out right now because the day after the terror attacks, the city is on edge as authors hunt for those responsible for the chaos. The death toll from the attacks now up to at least 31. At least 250 people injured. Brussels airport remains closed. The citys Transit System has limited service today. Molly hunter is in the belgian reporter on going raids continue across the european country. The manhunt for this man who authorities have identified as a suspect in the airport attacks. Investigators say it all started around 8 00 a. M. Tuesday morning. Two bombs exploding. The terminal filled with smoke, chaos, people frantically running for safety. Big bang. Everybody cried and came along here. We saw kind of moek smoke. Reporter the force so great, ceilings collapsed, people lying on top of one another and the horror continues. 9 11 a. M. An hour after the explosions seven miles away another bomb goes off near the offices of the european union. The target a packed metro car. Children screaming in fear. This is the first time i saw such a thing in my life. Reporter the aftermath leading to hundreds of injuries, among those nine americans richard are nor by, joseph empey and mason wells all seriously hurt. A city in mourning and messages of hope and condolences. Belgium remains at the highest Security Threat level tonight. Isis claiming those attacks just hours later. Now the state Department Warning americans against travel to europe saying terrorists are planning attacks right now. Molly hunter, abc news, brussells. Our thanks to molly hunter there in brussels. A lot of people, so many images coming out of brussels over the last 24 hours. Many people remembering the victims. The manhunt is on for that man on the right. People wondering what it means for Airport Security across the country, across the nation and across the world especia