WASHINGTON (AP) — The U.S. military has shot down a Turkish drone that had come in too close to U.S. troops on the ground in Hasakah, Syria.

That’s according to a U.S. official, who spoke to The Associated Press.

The official says the drone had been flying in an “unsafe” and “unsychronized” manner.

Typically, the U.S. and Turkish militaries, which are NATO allies, work in close coordination in conducting air maneuvers.

The official spoke on condition of anonymity to discuss the incident before an announcement.

The U.S. has about 900 troops in Syria conducting missions to counter Islamic State group militants.