One person was killed, and 10 others injured after a boat crashed into a jetty in Southern California.

The 48-foot boat crashed into the Alamitos Bay jetty around 9:20 p.m. Wednesday, the Long Beach Fire Department said in a news release Thursday.

While it is not immediately clear how many people were on board, authorities said the "mass casualty incident" involved 11 victims.

One person was declared deceased on spot, while the other victims were transported to local hospitals, where three of them were identified as critical, authorities said.

Investigators did not specify a cause of the accident in their release. However, Long Beach Fire Department's Capt. Jack Crabtree told the Los Angeles Times that speed was likely a factor, with preliminary reports suggesting the boat was traveling at roughly 40 mph.

The captain added that an investigation into the incident is ongoing.