Two missing after crash of U.S. Navy helicopter in Red Sea September 22, 2013 -- Updated 2103 GMT (0503 HKT) Three crew members were found in stable condition The crash "was not due to any sort of hostile activity," Navy says (CNN) -- Three crew members aboard a U.S. Navy helicopter that crashed in the Red Sea on Sunday were found alive and in stable condition, the Navy said. Two others remained missing. The MH-60S Knighthawk was operating with the guided-missile destroyer USS William P. Lawrence when it went down in the central Red Sea, which lies between Africa and the Arabian Peninsula. Search efforts are under way for the two remaining crew members. The cause of the crash is under investigation; however, the Navy said it "was not due to any sort of hostile activity." Four die in North Sea helicopter crash Five dead in Pennsylvania helicopter crash