Tokyo, Dec 11 (IANS): Five US marines missing after an air accident off Japan last week have been declared dead and the search for them has been called off, the US Marine Corps said on Tuesday.

"I have made the determination to end the search and rescue operations for the crew of our KC-130J aircraft which was involved in a mishap off the southern coast of Japan and to declare that these Marine warriors are deceased," Marine Corps Lt. Gen. Eric Smith, commander of the III Marine Expeditionary Force, said in the statement.

"Every possible effort was made to recover our crew and I hope the families of these selfless Americans will find comfort in the incredible efforts made by US, Japanese, and Australian forces during the search," he said.

The identities of the Marines were not released, but the Marine Corps said their next of kin were notified, CNN reported.

US, Japanese and Australian forces conducted more than 800 hours of air and maritime search operations, covering more than 35,000 square miles of ocean, US Forces Japan said in a statement.

The five Marines were among seven crew aboard two planes -- a KC-130 Hercules tanker and F/A-18 Hornet fighter -- that collided last Thursday about 320 km off the coast of Japan.

The aircrafts were performing routine aerial manoeuvers that included refuelling exercises in flight, although the US military was unable to confirm whether that particular action was the source of the accident, which was still being investigated.

Of the total seven crew members from both planes, one was rescued alive on the day of the accident and was stable after receiving medical attention. One more Marine was rescued but was later declared dead.

Search and rescue operations lasted five days.

The accident occurred two weeks after a US fighter FA-18 crashed into the sea southeast of Naha, Okinawa, after taking off from the nuclear-powered aircraft carrier USS Ronald Reagan, without any casualties.