The Air Force says it has grounded all T-38C training jets following the second fatal crash involving the aircraft in eight days.

Military authorities say two pilots died early Thursday when their high-altitude, supersonic jet crashed at Sheppard Air Force base in northern Texas.

A public affairs spokeswoman says the plane was assigned to the 80th Flying Training Wing, which trains combat pilots for NATO.

Two pilots died April 23 when their training jet crashed at Columbus Air Force Base in Mississippi.

The Air Force has suspended all T-38 flights pending investigations into what caused both crashes.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP’s earlier story is below.

WICHITA FALLS, Texas (AP) _ Two pilots in a training jet crashed at Sheppard Air Force base and died early Thursday, the second fatal wreck involving a T-38C Talon in less than two weeks, officials said.

The two-seater, high-altitude supersonic jet went down about 7:45 a.m. The plane was assigned to the 80th Flying Training Wing, a multinational organization that produces future combat pilots for NATO.

The pilots’ names and countries of origin were not immediately released.

Two pilots in a T-38C died eight days ago at Columbus Air Force Base, Miss. Investigators are trying to determine what caused both crashes.

“At this point we have no indication that there was any tie between the two,” said Capt. John Severns, Chief of Media Relations for Air Education Training Command at Randolph Air Force Base near San Antonio.

Thursday’s accident was at least the sixth fatal plane crash involving Sheppard base personnel in 10 years, and the third involving a T-38C Talon trainer jets since 1995.

Seven T-38 Talons have crashed since 1997, resulting in four deaths, according to the Air Force Safety Center.

The Talon, primarily used by the Air Education Training Command, was first deployed in 1959, according to an Air Force Fact Sheet.

“We have an extensive training program,” Severns said. “The T-38 is just a part of that program ... . The T-38 happens to be the trainer we use for those in the fighter training pipeline.”

Pilots from 13 NATO countries train through Sheppard’s Euro-NATO Joint Jet Pilot Training Program.

The T-38’s crew normally consists of a student pilot and instructor seated in tandem. Student pilots pick up aerobatics, formation flying, night and instrument flying, cross-country awareness, general maintenance awareness and supersonic techniques in the aircraft.

All Thursday flights at Wichita Falls’ Municipal Airport, which shares runways with Sheppard, were canceled, a city official told the Wichita Falls Times Record News.

Wichita Falls is about 135 miles northwest of Dallas.