msnbc.com

The CH-53 D Sea Stallion, with four Marines aboard, crashed about 7:20 p.m. Hawaii time Tuesday, Maj. Alan Crouch, with the Marines' public affairs office in Hawaii, told NBC News.

One died in the accident and the other three were at The Queen's Medical Center in Honolulu, Crouch said. Two survivors were in critical condition and the third in serious but stable condition.

The names and ages of the Marines were not immediately released, pending notification of next of kin.

It was not immediately clear what caused the crash.

The chopper went down while attempting an emergency landing in shallow water in Kaneohe Bay, the Honolulu Star-Advertiser reported. The helicopter left its base at Kaneohe Bay about 7 p.m. and crashed about 20 minutes later, 2nd Lt. Diann Olson, a Marine spokeswoman, told the newspaper.

The aircraft was resting on its side in shallow water, the newspaper said.