MEXICO CITY - Mexico's top transportation official said  a Learjet carrying Mexican-American music superstar Jenni Rivera plunged almost vertically from more than 28,000 feet and hit the ground in a nose-dive at more than 600 miles an hour.

Gerardo Ruiz Esparza, Mexico's secretary of communications and transportation, offered the first detailed accounts of the moments leading up to the crash that killed Rivera and six other people aboard the Learjet on Sunday.

Ruiz told Radio Formula that the plane hit the ground 1.2 miles from where it began falling, meaning it plummeted at a nearly 45 degree angle.

"The plane practically nose-dived. The impact must have been terrible," he said.

Esparza said the pilot of the plane, Miguel Perez Soto, had a valid Mexican pilot's license that would have expired in January.

The temporary pilot's certificate issued by the U.S. Federal Aviation Administration and found amid the wreckage indicated that the pilot was 78.

The National Transportation Safety Board sent a team to help investigate the crash of the American-registered Learjet 25, which disintegrated on impact in the rugged terrain in Nuevo Leon state in northern Mexico.

Alejandro Argudin, the head of Mexico's civil aviation agency, said there was no distress call from the plane before it crashed.

Rivera and her entourage had taken off from Monterrey, Mexico and their plane went off the radar a short time later.

Mexican authorities were using DNA to identify body fragments found at the crash site.