DUBAI, United Arab Emirates — A US Navy helicopter crashed Thursday in the Gulf nation of Oman with five crew members aboard, according to the US military.

An Omani air force official said three of them were found and were being treated in a hospital. A search was underway for the others.

Lieutenant Greg Raelson, a spokesman for the Navy’s Fifth Fleet in Bahrain, said an investigation is underway into crash of the MH-53E Sea Drago. No hostile activity is suspected.

Raelson said that the helicopter was involved in heavy lift operations when it crashed on land some 58 miles southwest of the capital Muscat.

A similar helicopter from the same squadron was on the scene carrying out search and rescue operations.

The downed copter is assigned to Helicopter Mine Countermeasure Squadron 15, which is based in Norfolk, Va.

The three-engine MH-53E is able to operate from aircraft carriers and other warships and is mainly used for minesweeping operations.

Oman lies on the southeastern corner of the Arabian Peninsula.