San Francisco, Sep 5 (IANS): The five missing crew members of an MH-60S helicopter which crashed off the coast of California last week, have been declared dead, the US Navy said.

In a statement on Saturday, the Navy said that the 3rd Fleet has shifted from search and rescue efforts to recovery operations, reports Xinhua news agency.

"The transition from search and rescue efforts to recovery operations comes after more than 72 hours of coordinated rescue efforts encompassing 34 search and rescue flights, over 170 hours of flight time, with 5 search helicopters and constant surface vessel search," the Navy statement added.

Assigned to Helicopter Sea Combat Squadron 8, the chopper was conducting routine flight operations from aircraft carrier USS Abraham Lincoln when it crashed into the sea approximately 60 nautical miles off the coast of San Diego on August 31, according to the Navy.

One crew member was rescued following the crash.

Five sailors aboard aircraft carrier USS Abraham Lincoln were also injured during the incident.

Officials said that an investigation into the incident is underway.

San Diego-based USS Abraham Lincoln is the fifth Nimitz-class aircraft carrier in the Navy and a member of the US Pacific Fleet.