A 7-ton truck overturned during a training exercise at Miramar air base early Saturday, killing one Marine and injuring 19 others, authorities said.

The truck was part of a six-vehicle convoy on regularly scheduled training when it went off a dirt road and overturned sometime after 3 a.m. at Marine Corps Air Station Miramar, base spokesman Maj. Todd Sudmeyer said.

The injured were taken to local hospitals but their conditions were not immediately released. Their identities also were not immediately released until relatives could be notified.

"The prognosis for the 19 wounded marines is good across the board," Sudmeyer said. "Even the most severe are stable and are expected to make a full recovery."

All were members of Miramar's 4th Tank Battalion, and training at the base was suspended while officials investigate the accident, Sudmeyer said.