A Navy statement Monday said officials determined the chance of survival was now considered "extremely unlikely" following Sunday's crash.
The MH-60S Knighthawk went down in the central Red Sea while operating with the destroyer USS William P. Lawrence.
The names of the missing airmen were not immediately released.
The Bahrain-based 5th Fleet says aircraft and vessels took part in the search. It said the crash was under investigation, but no hostile action was involved.
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