HANOI -- Ten Vietnamese fishermen were missing Wednesday, two days after their ship collided with another vessel and they last radioed a Vietnamese outpost on the disputed Spratly Islands, state media said.

The fishermen, from southern Phu Yen province, disappeared after their ship was hit by a vessel on Monday and sank, the state-run Vietnam News Agency (VNA) reported.

The VNA report said the accident happened 80 miles (about 130 kilometers) offshore, quoting the provincial Border Guard Command Office.

The Vietnamese ship "could not get into communication with land due to bad weather and only sent signals for help to the Truong Sa Marine Rescue and Search Center," the report added.

Rescue ships and a helicopter searched for the victims, though none have been found, VNA said.

Truong Sa is the Vietnamese name for the Spratly Islands, a potentially oil-rich South China Sea archipelago that is also claimed in full or in part by China, the Philippines, Malaysia, Brunei and Taiwan.