The U.S. military said it shot down an Iranian-made, armed drone in southern Syria on Tuesday, marking the third time this month that that the U.S. has downed aircraft affiliated with Syrian President Bashar Assad's government.

The message is clear: Back off.

The U.S.-led coalition fighting the Islamic State group said a U.S. F-15 fighter jet shot down the drone "after it displayed hostile intent" while approaching a military camp near the Syria-Jordan border. A similar drone was shot down in the same location after it dropped munitions near coalition forces on June 8.

The repeated incidents in the vicinity of the Tanf camp, where U.S. forces train and advise local ground forces in the fight against ISIS, add to soaring regional tensions that could spiral out of control just as the fight against the Islamic State enters a crucial phase, with U.S.-backed forces pushing into the group's de facto capital, the Syrian city of Raqqa.