An Air Force drone crashed into a Florida highway on Wednesday, starting a fire and shutting down the highway until sometime Thursday morning.

Tyndall Air Force Base announced the crash on Tuesday afternoon, stating that a QF-4 drone crashed while taking off from the base’s drone runway at around 8:25 a.m. EDT. No one was injured in the crash, but the drone apparently crashed into a stretch of the nearby Highway 98, located west of Panama City and east of Mexico Beach. Officials have not commented on why the drone accident took place.

The QF-4 drone, which reportedly started several small fires in the vicinity of the crash, is armed with a small self-destruct charge, which the Air Force believes may be a hazard to anyone approaching the downed vehicle. Because the self-destruct charge’s battery wears out after only 24 hours, officials have decided to close the nearby stretch of Highway 98 until the drone is confirmed safe to recover.

According to the Associated Press, QF-4 drones are built from modified F-4 Phantom jets, which have remained in service since the 1950s. They are in use at Tyndall Air Force Base and Holloman Air Force Base in New Mexico.

Military technology expert James Lewis tells the AP that the Air Force was likely using the QF-4 drone as target practice for its F-22 Raptors. Q4-F drones are remotely controlled from the Air Force base, and can simulate the actions of enemy aircraft.

“It is an older fighter plane they have modified for use as a target,” Lewis, who works with the Center for Strategic and International Studies, told the AP. “The QF-4 is not a drone in the way we normally think of drones. It is not used for anything other than to be shot down. It is an old aircraft that would otherwise be sold for scrap.”