backed fighters and local forces as they try to retake the city of raqqah. raqqah of course is the self declared capital of the self declared caliphate. >> ben wedeman, our senior international correspondent, joins us. give us a sense of how significant this move is. you now have not just a few but a significant number of u.s. marines on the ground in northern syria. >> reporter: poppy, it's important to keep in mind that the pentagon isn't saying how many marines are there. but we know what they're going to do. they're going in with 155-millimeter howitzers, long range artillery, a range of 20 miles. and they'll be participating in the offensive to drive isis out of raqqah. their role is important because i've been to that part of syria with the u.s.-backed forces in that area. they don't have much in the way