Transcript for New details released in Syrian terror attack that killed 4 Americans

Next this evening, new Dell tails on that suicide bombing that killed four Americans in Syria. The deadliest attack on U.S. Forces since American troops were sent there. ISIS is now taking responsibility, even as president trump just weeks ago said ISIS had been defeated. ABC's senior foreign correspondent Ian Pannell tonight, he's on the Syrian border. Reporter: Tonight, we're learning new details about the deadly suicide attack that ripped through this Syrian street. U.S. Officials telling ABC news the four Americans killed were part of a team gathering military intelligence. They were inside a restaurant frequented by U.S. Military when the bomber blew himself up in the doorway. American intelligence concluding it was an ISIS attack. The president today making his first comments on those lives lost. I want to take a moment to express my deepest condolences to the families of the brave American heroes who laid down their lives yesterday in selfless service. Reporter: Just weeks ago, the president announced plans to withdrawal, at the time, declaring victory against ISIS. We have won against ISIS. We've beaten them and we've beaten them badly. Reporter: But on the ground, we've seen the battle against ISIS up close, and Syrians in that same town told us only last year how they feared a U.S. Pullout. ISIS would have an opportunity to re-emerge. Reporter: This was the deadliest attack on Americans during this war by an enemy determined to show the U.S. It may be down, but it isn't out. And Ian Pannell reporting in tonight from Iraq, not far from the Syrian border, of course, and Ian, you've reported from inside Syria often for us, and as far as you can tell, Ian, for all the talk that ISIS has been defeated, from the folks you're talking to on the ground there, what is the current situation? Reporter: David, I think it's fair to say that ISIS is a shadow of its former self. It's down, but it's not beaten. The front line battles are still raging. And experts say that ISIS today, not just in Syria, but here in Iraq, representing a graver threat than Al Qaeda ever did here, even in its hay day. David? All right, Ian Pannell and our team in Iraq tonight. Ian, thank you.

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