U.S. shoots down drone over Syria that fired at coalition troops No one was injured in the incident, the coalition said.

 -- A U.S. Air Force fighter jet shot down an armed Predator-like drone over southeastern Syria on Thursday after the drone had fired at coalition and Syrian rebel forces, according to a coalition statement. No one was injured in the incident.

Earlier in the day coalition aircraft carried out an airstrike on two vehicles belonging to a pro-Assad regime militia force that were moving towards the town of At Tanf where the coalition runs a training center for local Syrian rebels fighting ISIS. The incidents are the latest escalation between the coalition and the pro-regime militia forces in the remote region of Syria.

"The pro-regime UAV, similar in size to a U.S. MQ-1 Predator, was shot down by a U.S. aircraft after it dropped one of several weapons it was carrying near a position occupied by Coalition personnel who are training and advising partner ground forces in the fight against ISIS," said a statement issued by Operation Inherent Resolve.

None of the coalition or partner forces on the ground were injured by the drone's weapon, but it was considered a threat and was shot down by an F-15E fighter jet.

Colonel Ryan Dillon, the coalition spokesman in Baghdad, told Pentagon reporters that the drone attack was the first time that pro-Assad forces had fired at coalition forces in the area.

Dillon said an assessment was underway to determine the drone's origin. U.S. officials have said that the pro-Assad regime force operating around at Tanf is a militia backed by Iran.

Earlier in the day U.S. aircraft carried out an airstrike targeting two armed trucks that had entered the "deconfliction zone" that extends in a 34 mile radius around at Tanf. The zone is one of several established in Syria in areas where both coalition and Russian forces are operating.

The airstrike was the second carried out this week and the third overall since May 18 against armed forces from the Iranian-backed militia.

The pro-Regime forces were struck after entering the deconfliction zone around At Tanf and ignoring repeated warnings to turn back.

"The Coalition's mission is to defeat ISIS in Iraq and Syria," said the statement from Operation Inherent Resolve. "The Coalition does not seek to fight Syrian regime, Russian or pro-regime forces partnered with them. The demonstrated hostile intent and actions of pro-regime forces near Coalition and partner forces in southern Syria, however, continue to concern us and the Coalition will take appropriate measures to protect our forces."