KATHMANDU: Twenty-one people sustained injuries in an explosion and fire Sunday on board a ship at Naval Base San Diego, international media reports said.

The fire broke out shortly before 9 am on USS Bonhomme Richard, Associated Press quoted Mike Raney, a spokesman for Naval Surface Force, US Pacific Fleet, as saying.

Seventeen sailors and four civilians were hospitalized with “non-life threatening injuries,” Raney said in a brief statement. He didn’t provide additional details.

Previously, officials said at least one person was treated for smoke inhalation. The flames sent up a huge plume of dark smoke visible around San Diego.

San Diego is the Bonhomme Richard’s home port, and the ship was undergoing routine maintenance at the time of the fire.

About 160 sailors and officers were on board, Raney said — far fewer than the thousand typically on the ship when it’s on active duty.

(With inputs from Agencies)