Doug Stanglin

USA TODAY

The U.S. Coast Guard was searching for survivors Friday after two Marine Corps helicopters carrying 12 people collided off the Hawaiian island of Oahu.

There was no immediate word on the fate of the crewmembers of the two heavy-lift transport helicopters or what caused the collision.

Searchers, in their initial survey of the area, spotted a fire, a debris field and an empty life raft 2 ½ miles off the coast, near the town of Haleiwa, but no sign of survivors. The search and rescue operations were underway in areas with a high surf advisory, including likely 10-foot waves, Honolulu's KHON-TV reported.

Coast Guard Chief Petty Officer Sara Mooers told The Associated Press that the Marine Corps reported the collision just before midnight. Mooers said each aircraft had six people aboard.

KHON-TV reported witnesses in the area heard a loud boom over the water and saw a big flare in the sky.

The Navy destroyers Gridley and John Paul Jones were taking part in search and rescue efforts along with the Coast Guard cutter Kiska and an MH-65 Dolphin helicopter from Coast Guard Air Station Barbers Point, officials said, according to Marine Corps Times.

A Coast Guard A C-130J was also part of the search but had to land when a bird struck it, said Coast Guard spokesman Lt. Scott Carr.

Marine Corps Base Hawaii posted a message on its Facebook page asking members of the public not to touch any debris from the helicopters that washes ashore and to respect any local police or fire department cordons around debris. "Please note the location of debris and we will provide you a number to call very shortly," the message says.

The two CH-53s are from the 1st Marine Aircraft Wing from Marine Corps Base Hawaii. helic

It is the second crash by a military aircraft in less than a year in Hawaii, and the second involving a military helicopter in four years, the Honolulu Star Advertiser reports. Two Marines were killed and several were injured in a crash landing at Bellows Air Force Station in Waimanalo, Hawaii in May. In 2012, one person was killed and three injured when a CH-53D Sea Stallion made a "hard impact" landing while on a night training flight.

Contributing: Marine Corps Times