A U.S. Army Special Forces' helicopter has crashed into the sea off the southern Philippines with at least 10 soldiers on board. Apparently no survivors were found after hours of searching, but local media reported that some bodies have been recovered

Officials say the helicopter crashed into the sea off Negros Island, a few kilometers from a U.S. staging base near Cebu.

The large twin-rotor craft, called the Chinook, took off after midnight Friday from Basilan Island, where U.S. Green Berets are training Philippine troops that are pursuing Abu Sayyaf guerrillas.

U.S. officials said the helicopter went down about two o'clock in the morning. A second helicopter that was accompanying it, conducted search operations aided by U.S. and Philippine planes. Officials say there were no reports of hostile fire.

For the past week, the helicopters have been ferrying 160 U.S. Special Forces troops to Basilan to equip and train Philippine soldiers for night operations.

The helicopters have been operating several missions a night, flying without lights and using sophisticated night vision equipment.

This is the first crash by U.S. forces in the Philippines since the start of the joint exercises called Balikatan, or shoulder-to-shoulder.

U.S. officials say the exercises are part of the war on international terrorism. They are the first U.S. military deployment abroad since the operation in Afghanistan.

The Abu Sayyaf guerrillas have been linked to the al-Qaida terrorist group. They say they want to form an Islamic state in the southern Philippines, but mostly they have engaged in murder and kidnapping for ransom.

The Philippine government calls the Abu Sayyaf a criminal gang and has vowed to crush it.