Report: Iran holds US responsible for safety of Iranians captured by Syrian rebels

The Obama administration has thus far publicly shied away from arming the rebels, but is in contact with them and has delivered communications equipment and allowed the CIA to provide covert assistance. The administration hopes that the fall of President Bashar Assad will lead to a break in relations between Syria and Iran, further isolating Tehran as the international community tries to get it to abandon its alleged nuclear weapons program.

The Iranians' detention comes as Assad's regime continues to crumble, with his prime minister reportedly defecting to Jordan on Monday.

“As we've said repeatedly as we've seen more and more high-level defections, this is a sign that Assad's grip on power is loosening,” White House spokesman Jay Carney said Monday. “If he cannot maintain cohesion within his own inner circle, it reflects on his inability to maintain any following among the Syrian people that isn't brought about at the point of a gun.”