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News about the uncertainty of their whereabouts came a week after the rebels were attacked by 50 fighters from the rival al-Nusra Front, a rebel group affiliated with al Qaeda. At least one of the U.S.-trained rebels was killed and others were wounded before the attack was repelled by U.S. airstrikes.
The Pentagon said earlier this week that President Obama had authorized airstrikes to defend the rebels, even from forces loyal to Syrian President Bashar al-Assad.
The U.S. must rely on the 54 rebels, known as the New Syrian Forces, to report their movements since they fall under the U.S. chain of command, Pentagon spokesman Capt. Jeff Davis said earlier Thursday. He said they have the means to communicate with the U.S. military, but that it didn't mean they provided regular updates about their positions.
Davis added that tracking them was made difficult by current combat conditions in northern Syria.
The small group of rebels recently began operating after becoming the first graduates of a U.S. program that plans to train and equip as many as 5,400 moderate Syrian opposition forces to fight ISIS.
But the $500 million training program for the rebels has been slow to begin because of a vigorous vetting program intended to ensure that potential recruits will not join other extremist groups or fight the Assad regime. So far, the Pentagon has spent $42 million to start up the program.
Davis said a second group of fighters is currently undergoing training and indicated that they would become trainers themselves. A third group of Syrian rebels will begin training shortly afterwards, he said.
At least 1,500 Syrian rebels have been vetted for the program and several thousand more volunteers remain to be vetted.
Davis said the Pentagon remains committed to the program’s success, but when asked to characterize the initial deployment of rebels in Syria, he called it challenging but added that it was inaccurate to say the U.S. was caught “totally flat-footed by the idea of sending people into a very dynamic and rapidly changing war zone.”