The U.S. Navy is looking for five crew members who were aboard an MH-60S helicopter when it crashed off the coast of San Diego during routine flight operations Tuesday afternoon.
One additional crew member was rescued, transported ashore and is in stable condition, military officials said.
The Navy said it is investigating the cause of the crash, which occurred about 60 nautical miles from the Southern California city. The helicopter had been aboard the aircraft carrier USS Abraham Lincoln, which has its home port in San Diego.
According to a statement, the aircraft from Helicopter Sea Combat Squadron 8 was operating on deck before it crashed into the water.
Five additional sailors aboard the carrier were injured but are in stable condition. Two sailors were transported ashore for treatment, while three who had minor injuries stayed on board.
"We ask that you please respect the privacy of the families of our shipmates directly affected by this tragedy, and keep all of Lincoln Nation and our embarked shipmates in your thoughts and prayers during this incredibly difficult time," said a post on the USS Abraham Lincoln's Facebook account.
U.S. Coast Guard and Navy air and surface crews are conducting the search and rescue operation, officials said.