A medical helicopter transporting a patient crashed Wednesday evening off Catalina Island near Los Angeles, killing two, authorities said. 

Two people in the crash have been hospitalized, and rescuers are seeking a fifth person who was aboard the aircraft but went missing, the Associated Press reported. 

Coast Guard Capt. Stacey Crecy said at a news conference that the Coast Guard area firefighters and divers with the Los Angeles County Sheriff’s Department were among emergency personnel who are involved in the rescue. 

Crecy said the helicopter went down shortly after takeoff and hit the water a short distance from the island. The cause of the crash was not immediately clear.