An MH-60S Knighthawk helicopter assigned to Helicopter Sea Combat Squadron 6 crashed in the central Red Sea while operating with the guided-missile destroyer USS William P. Lawrence, the U.S. Naval Forces Central Command public affairs office said in a release posted on the Navy's website.
"Three personnel are accounted for and stable. Search efforts continue for two remaining personnel.
"The crash was not due to any sort of hostile activity," the statement said, though it said the incident was under investigation.
The public affairs office said the Lawrence, the USS Nimitz, USS Princeton, USS Shoup, USS Stockdale and USNS Rainier were taking part in the search along with aircraft from HSC-6, Helicopter Maritime Strike Squadron 75 and Patrol Squadron 47.
The MH-60S Knighthawk helicopter was either trying to take off or land about noon local time on the rear helicopter deck of the Lawrence, a guided-missile destroyer, when the accident took place, NBC News reported.