Two people were killed and three injured Saturday when a fire erupted aboard a 35-foot power boat, according to the Long Beach Fire Department.

The blaze occurred near a fueling dock in Alamitos Bay in the 200 block of Marina Drive, according to officials.

Two women in their 60s were killed and three others — two men and one woman, also in their 60s — were taken to hospitals with burn-related injuries, Long Beach Fire Capt. Jake Heflin said.

He said that firefighters responded to a call about a blaze at 5:17 p.m. and dispatched fire engines and marine safety rescue boats to the scene. Bystanders were trying to extinguish the flames and told rescue workers that the pleasure craft was in the process of fueling at the time, but the exact cause of the fire is under investigation, Heflin said.

Firefighters “knocked a good portion of the fire out” with water cannons, Heflin said, but called in county firefighting support to make sure the blaze did not spread wind-driven embers onto other boats or the fueling dock.

The fire sent up a massive cloud of black smoke that was visible for miles as firefighters battled the flames from the ground and the water.

Daniel Quinn, a host at the nearby Crab Pot restaurant, said he heard a loud explosion, “like someone landed on the roof.”

“There was a big bang and I looked up, and there was this ginormous plume of black smoke,” he said.

Heflin said booms were placed around the damaged boat to minimize any environmental impact caused by potential fuel or oil leaks. But as rescue workers moved the boat to an isolation dock, it began to take on water and is now partially submerged. Long Beach officials plan to use a private salvage company to remove the boat from the water, he said.

He added that no firefighters were injured but they will be offered mental health services if needed to process any trauma from the experience.