Mexico City -- The plane 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 a speed that may have exceeded 600 miles per hour, Mexico's top transportation official said Tuesday.

In the first detailed account of the moments leading up to the crash that killed Rivera and six other people, Secretary of Communications and Transportation Gerardo Ruiz Esparza told Radio Formula that the twin-engine turbojet hit the ground 1.2 miles from where it began falling.

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

Ruiz did not offer any explanation of what may have caused the plane to plummet, saying only that "The plane fell from an altitude of 28,000 feet ... It may have hit a speed higher than 1,000 kph (621 mph)."

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