A 23-ton Marine Corps amphibious vehicle sank last night while conducting a platoon training exercise off Marine Corps training area Bellows, officials said.

There were no injuries to crew members, who were safely evacuated by another assault amphibious vehicle, or AAV, participating in the training exercise, Marine Corps Base Hawai'i said.

The Corps said the AAV was hit by a swell more than half a mile off shore.

The wave caused the tracked vehicle to strike a reef, and it began taking on water, officials said. The Combat Assault Company AAV Platoon was conducting scheduled AAV water operations.

The tracked vehicle lost power while attempting to reach the shoreline and subsequently sank at about 6:30 p.m. approximately 500 feet from shore, officials said.

The Coast Guard was informed and vehicle recovery operations are expected to begin today.

AAVs are the Corps' current amphibious troop transport and are used by Marines to move from ship to shore. The vehicles can carry up to 25 Marines in addition to a crew of three.

Marine Corps Base Hawai'i said the incident is under investigation.