RACHEL MARTIN, HOST:
The latest on that attack last night in Manchester, England. Twenty-two people were killed, including the attacker; more than 50 others injured. Police say children are among the dead. Police are treating the attack as an act of terrorism. And this morning, the Manchester Police arrested a 23-year-old man in connection with the attack. They've also arrested a second man, who they say may not be connected. Speaking in Bethlehem, President Donald Trump called on all countries to unite in fighting terrorism.
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PRESIDENT DONALD TRUMP: So many young, beautiful, innocent people, living and enjoying their lives, murdered by evil losers in life. I won't call them monsters because they would like that term. They would think that's a great name. I will call them from now on losers because that's what they are. They're losers.
MARTIN: We're joined now in the studio by national security correspondent Mary Louise Kelly. Hi, Mary Louise.
MARY LOUISE KELLY, BYLINE: Hey, Rachel.
MARTIN: Is there any word yet on who might have been responsible, anyone taking responsibility?
KELLY: Well, here's the latest - officials in the U.K. believe they know the identity of the bomber. The prime minister, Theresa May, came out and said, we think we know who it is, but we're not releasing that name to the public yet. Meanwhile, we have seen ISIS supporters celebrating online. And we just have seen a claim of responsibility on an official ISIS account. The quick rough translation from Arabic says that soldier of the caliphate carried out the attack. Now, let me inject a strong note of caution here because, as always in these early hours after an attack, the picture is changing really fast. If this was ISIS, we don't know if it was ISIS-directed, ISIS-inspired, what the nature of the link may be. The other latest development, as you mentioned, there are - the suicide bomber died in the attack. But U.K. officials initially thought this was one person acting on his own. You have now mentioned there are a couple of other arrests. So the picture is changing. Is there a connection? We don't know. Was the bomber acting alone, or maybe as part of a network?
MARTIN: Still unfolding.
KELLY: Right.
MARTIN: So investigators, at this moment, are going to be poring over all sorts of physical evidence. What types of things are they looking for?
KELLY: Right. Well, sadly, there is a playbook for this sort of thing now. This is the deadliest terror attack in Britain since 2005 - those July 7 attacks in London. However, we remember that just two months ago in March, there was this attack on Westminster Bridge outside Parliament in London in which five people - four pedestrians and a police officer - died. And so in cases such as this where there was a bomb involved - to your question of physical evidence and what are they looking at - they're looking at, among other things, what kind of bomb residue there was. Different terror groups use different signature explosives. ISIS has made a signature out of using TATP. That stands for triacetone and triperoxide. We saw them use that in Berlin, in Brussels, in Paris. If that turns up again in Manchester, that would be a significant piece of evidence.
MARTIN: What are American national security officials saying about the attack? Clearly, I'm sure, giving condolences. Anything else?
KELLY: Of course. I mean, we heard President Trump weighing in from Bethlehem this morning. The Department of Homeland Security has put out a statement, saying they have no intelligence indicating a credible threat here in the U.S., no information pointing that there may be copycat attacks. They say we may well see increased security in public places today just as a precaution. And meanwhile, something to watch for this morning, the director of national intelligence, Dan Coats, was by coincidence already slated to testify before a Senate committee this morning. The subject of that hearing is worldwide threats. And you can guess which question just shot to the top of the agenda. He'll be asked the state of the terror threat...
MARTIN: Terrorism.
KELLY: ...Worldwide, yeah.
MARTIN: So while we've got you, Mary Louise, let's pivot to another big national security story playing out this morning - more developments in the Russia investigations. Former CIA Director John Brennan is testifying this morning, and there are new twists involving Michael Flynn, the former national security adviser. Bring us up to date.
KELLY: Sure. The legal challenges for Mike Flynn continue to mount. The two twists to note this morning - one, Michael Flynn is refusing to comply with a subpoena from the Senate intelligence committee. They had asked him to produce documents. He says he's invoking the Fifth Amendment, his right not to self-incriminate, and he's not going to hand over those documents. So next move, Senate. We wait to see what they may do to try to force his hand or try to get those documents another way. The second development, I mentioned there are two, and the second one to watch is on the House side. A top Democrat, Elijah Cummings of Maryland, says he has documents that suggest Flynn may have lied to investigators last year. These were security clearance investigators trying to line him up with his renewed security clearance, and they were conducting background checks. And according to Cummings, Flynn produced misleading information.
MARTIN: So before you leave, you mentioned John Brennan, former director of the CIA, testifying. What are we expected to hear from him?
KELLY: Right, first time since he left the CIA back in January. And he - one of this - one of the key questions here is Congress is trying to figure out its next move, where their investigations into the Russia probe should go now that the FBI has accelerated its investigation under a special counsel. So those are some of the questions that we'll be watching for later today.
MARTIN: NPR national security correspondent Mary Louise Kelly, thanks so much.
KELLY: You're welcome.
[POST-BROADCAST CORRECTION: A previous version of this story placed Bethlehem in Israel. In fact, Bethlehem is in the West Bank.] Transcript provided by NPR, Copyright NPR.