Two airmen are dead after two U.S. Air Force T-38 Talons were involved in an unspecified “mishap” at Vance Air Force Base in Oklahoma, officials said Thursday.

“At the time of the accident, the aircraft were performing a routine training mission,” officials said on the base’s Facebook page. “There were two people onboard each aircraft.”

Emergency personnel are on the scene assisting, but officials have not released any information on any casualties or injuries.

A base spokesman confirmed to Air Force Times the accident happened about 9:15 a.m. CST.

This story will be updated as details become available.