A US Army helicopter with 12 American troops on board crashed in the Philippines today.
No survivors were found, the Pentagon said.
The Defense Department said no hostile fire was reported when the crash occurred and that the CH-47 chopper crashed into the sea in darkness while flying from Basilan to Mactan Air Base.
The helicopter went down about 120 miles north-northwest of Zamboanga, according to the US army.
The incident occurred as a growing number of US forces were arriving in the Philippines to take part in training exercises in which Manila's military is conducting a stepped-up battle against Muslim rebels.
Some 6,000 Philippine troops are on the southern Philippine island of Basilan and 160 US special forces will be there until June to train them. Another 500 US support personnel will be in the nearby city of Zamboanga and in the central city of Cebu.
US special forces troops moved into the southern Philippines last month for joint exercises with the Philippine military aimed at wiping out Abu Sayyaf guerrillas, linked by Washington to fugitive Osama bin Laden's al-Qaeda network.