Two Marines with the 1st Marine Division sustained gunshot wounds Sunday during a live exercise aboard the Corps’ sprawling Twentynine Palms, California combat training base.

One Marine has been released from the hospital while the other remains in serious condition, according to a command release.

The Marines with 3rd Battalion, 4th Marines were conducting a maneuver under fire during the training exercise when they were injured, 2nd Lt. Samuel Banks, a Marine spokesman, said in an emailed statement.

“Both Marines were evacuated by air ambulance to receive proper medical care for their injuries,” he said.

The Corps is describing the incident as a “training accident.”

“Military training is an inherently dangerous task and the 1st Marine Division takes every precaution to ensure the safety of our training,” Banks said. “Our commitment is to ensure that our training is as safe as possible. The training we conduct ensures our readiness to respond to any task we are assigned.”

Marine officials say the accident currently is under investigation.

In January 2017, one Marine was killed and another wounded during a live-fire small arms shoot aboard Twentynine Palms.