The White House and the Pentagon have repeatedly ruled out "boots on the ground" in Syria, but Defense Department officials were less certain Thursday on whether U.S. military personnel might be sent to help secure or destroy Syria's chemical weapons.

Pentagon Press Secretary George Little gave a vague answer when asked if U.S. troops were prepared to assist should an international agreement allow Russia to take control of the tons of chemical weapons believed to be in the stockpiles of President Bashar al-Assad.

"I'm not going to speculate on who may or may not be participating in a process that may or may not take place," Little said. "We've got to see where the process goes" before the U.S. military considers involvement, he said.