Reuters news agency reported Under Secretary of Defense for Policy Christine Wormuth as saying that the Pentagon will provide "basic kinds of equipment" to leaders of the groups, not "higher end" arms like anti-tank rockets and MANPADS.
Wormuth defended the $500m Pentagon programme that trained only 60 fighters, falling far short of the original goal of 5,400, Reuters reported.
"I don't think at all this was a case of poor execution," Wormuth said. "It was inherently a very, very complex mission."
The CIA runs a separate, covert programme that began in 2013 to arm, fund and train a moderate opposition to Assad. US officials say that effort is having more success than the one run by the military, which only trained fighters willing to promise to take on the ISIL exclusively.
The change in focus comes at a time when the Obama administration is also grappling with a dramatic change to the landscape in Syria's four-year civil war in the wake of
Russian military intervention.