Three soldiers die in California during training

WASHINGTON (CNN) -- A training accident killed three soldiers and wounded another at the Fort Irwin Training Center in California's Mojave Desert early Friday, Army officials at the Pentagon said.

About 5,000 soldiers from the 1st Infantry Division's 1st Brigade, based in Fort Riley, Kansas, were training in what officials call a "live fire exercise" at Fort Irwin when a 120mm mortar round exploded near some of them.

It appeared a shell exploded while it was still in a "M1064 mortar carrier," an apparatus that conveys the round to the gun, military sources told CNN.

The soldier who was injured is in stable condition at Weed Army Hospital on the base, said Capt. David Isaac, an Army spokesman at Fort Irwin.

Isaac said the monthlong training exercise was scheduled two years ago.

Officials have not provided any other details as an investigation begins.

Fort Irwin is located in the high desert of Southern California, about 120 miles northeast of Los Angeles.

CNN Producer Mike Mount contributed to this report.