Two Air Force Airmen were killed Thursday morning during an “aircraft mishap” at Vance Air Force Base in Oklahoma, officials said.

“Two Vance Air Force Base Airmen were killed in an aircraft mishap at approximately 9:10 a.m. today,” the Air Force said in a statement. “At the time of the accident, the aircraft were performing a training mission.”

An earlier statement from Vance said that two T-38 Talons were involved, and there were two people on board each craft. The status of the other two pilots was not immediately clear.