The Pentagon says it has started training moderate Syrian rebels to fight against Islamic State militants on the ground in Syria.
U.S. Defense Secretary Ashton Carter told reporters Thursday that 90 highly-vetted individuals began training at a secure location, which he did not disclose, and that the program will gradually expand.
"This is a complex program. It's going to have to evolve over time," Carter said. "We're starting with the people ... that we vetted very carefully. We're figuring out what the best training is, what the best initial deployment is. We expect that to be successful and therefore to grow. But you have to start somewhere."
The Obama administration has said almost since the start of the Syrian civil war that it supports the moderate opposition.
But some in Congress had complained that the training mission was too slow in getting started and that the primary purpose and exactly who would be trained was unclear.
Carter said Thursday that the principle mission of the rebels would be engaging Islamic State, and that is what they are being trained and equipped to do.
But he said the U.S. has what he calls a "responsibility" if the rebels find themselves fighting against Syrian troops.
"We have not decided yet in detail how we would exercise that responsibility, but we have acknowledged that we have that responsibility," Carter said.
The U.S. has targeted Islamic State in Syria with airstrikes, but has not attacked Syrian forces.
Some material for this report comes from AP, AFP and Reuters.