DAVID GREENE, HOST:
This week, U.S. troops came under artillery fire in Syria. None of them were killed, fortunately, and they repelled this attack with massive air power. But it was a sign of how the fight against ISIS is getting more complicated even as the Islamic State has largely been routed. Some of the local forces fighting with the United States are now more worried about other threats, including from Turkey, maybe even Russia, than they are about ISIS. NPR's Tom Bowman has just spent three days with some of the U.S. troops in Syria and saw how close the ISIS battle is fraying at the edges, and he joins us now from Kuwait. Hi, Tom.
TOM BOWMAN, BYLINE: Hey, David.
GREENE: All right. So there are some 2,000 U.S. troops in Syria, some of them attacked on Wednesday. Who was attacking them?
BOWMAN: Well, David, they were Syrian regime militias backed by Russia. And 500 of these fighters, using tanks and artillery, attacked a U.S.-supported Syrian rebel base, and there were some American military advisers there. Now, these artillery attacks, David, came within a few hundred yards of that rebel base. And we talked to the commander of the Syrian rebels in the area. He said he called the Russians because there's a formal process in place to make sure there are no military mishaps, accidents. That kind of communication is fairly routine. Here's the thing. He said the Russians denied there was any attack. Let's listen.
UNIDENTIFIED MAN: (Through interpreter) They deny. They say, we don't have any information about this attack.
BOWMAN: Here's the thing, David. The Russians were only six miles away and would likely have heard something going on. And after the U.S. responded with air attacks that killed a hundred of these Syrian regime militia fighters, the commander said the Russians called and said, can we come pick up the dead? The Russian government has since said there was an attack and those Syrian regime militias were actually going after ISIS fighters when the U.S. hit them. The Syrian regime, meanwhile, is calling the U.S. air attack a war crime.
GREENE: OK. So complicated because you have the U.S. operating there, you have the Syrian regime. You have the Russians and the U.S. and Russians - I mean, U.S. and Russia, that tense relationship, but trying to make sure there are no misunderstandings on the ground. And all the while, you have these other players there, right, Tom? You have the U.S. with Kurdish allies who have been preoccupied by this Turkish military offensive against them. What are the Kurds saying about what they're able to do right now to help the United States?
BOWMAN: Well, we did talk with Kurdish commanders and troops, and they are worried even more now. Hundreds of their fighters are heading up north to fight the Turks, who consider all Kurdish fighters terrorists. My producer Greg Dixon and I went to an outpost in the north where the Kurds often come under fire from Turkish-backed militias. And now with the Syrian militia attack farther south, the Kurdish commanders are sending their reserve forces down to that base to shore up defenses. And all of this is pulling troops and resources in the fight against ISIS. That's why the U.S. is here in the first place.
GREENE: Well, you say that's why the U.S. is there in the first place, but it sounds like it's in many ways becoming a complicated mess, though administration officials say that the U.S. is there to stay in Syria indefinitely. What do the commanders on the ground say about that?
BOWMAN: Well, what the military would say here is that it will take another two to six months to finally defeat ISIS, to eliminate that caliphate, and another year or more to stabilize this area with humanitarian aid and then small projects like water purification plants, electric substations, get, you know, basic services back. But this is where it all gets more complicated. The Syrian government and their Russian ally say the U.S. is here illegally. They were never invited in like Russia or Iran, who support the Syrian regime. And even some on Capitol Hill, like Senator Tim Kaine of Virginia, questions a U.S. presence after ISIS is defeated. He says, listen, the U.S. could be stumbling into a broader conflict without any clear objectives or, he says, without a vote in Congress.
GREENE: Because the objective was clear, which was to defeat ISIS.
BOWMAN: It was to defeat ISIS, but now what you're hearing from people like Defense Secretary Jim Mattis is we're going to stay to prevent the return of ISIS 2.0, and we're going to make sure the peace process, the talks in Geneva, take hold.
GREENE: NPR Pentagon correspondent Tom Bowman has just spent some time in Syria and joins us to talk to us about it from Kuwait. Tom, thanks a lot.
BOWMAN: You're welcome, David. Transcript provided by NPR, Copyright NPR.