Seventeen sailors and four civilians were reported injured Sunday after an apparent explosion and fire on a military ship in San Diego.
Firefighters were still battling the blaze early Monday morning on the USS Bonhomme Richard, Naval Surface Force said in a statement.
Federal Fire San Diego, which serves naval installations and facilities in the area, was leading the effort, the statement said.
Rear Adm. Philip Sobeck, commander of Expeditionary Strike Group 3, told reporters that according to initial reports, pressurization caused the explosions. He did not provide additional details.
Responding firefighters had to be mindful of the ship's million-gallon fuel hold.
"That was the priority all day to make sure that that was not affected," Sobeck told NBC San Diego.
San Diego Fire-Rescue said it responded at about 9 a.m. when a second alarm was called. A third alarm was called at 9:51 a.m., the department tweeted.
All firefighters from the San Diego department were accounted for by 11:19 a.m.
Naval Base San Diego tweeted that 17 sailors and four civilians were taken to the hospital for non-life-threatening injuries.
And by Monday morning, five sailors were still in "local hospitals for observation" and all were "in stable condition," according to the Navy.
About 160 crew members were on board. The ship was evacuated, and all crew members were accounted for, a Navy Southwest spokesman told NBC News.
Sobeck said the wounded suffered smoke inhalation and heat exhaustion.
Two nearby ships — the USS Fitzgerald and the USS Russell — moved to different berths to escape possible damage from the fire, the base said.
Krishna Jackson, public affairs officer for Naval Base San Diego, told NBC San Diego that the ship had undergone a regular maintenance cycle before the fire was reported.
The Bonhomme Richard is an amphibious assault ship, which works to deploy and land elements of a Marine landing force. San Diego became home to the ship in 2018 after it was docked for six years in Japan, according to the U.S. Naval Institute.