Hanoi - An oil tanker exploded and sank early Wednesday at a port in southern Vietnam, leaving three crew members missing, state media reported.

Vietnam News Agency said that just after 2 am (1900 GMT), a series of explosions occurred on board the 1,800-ton tanker Nhat Thuan while it anchored some 6 kilometres off the harbour of Vung Tau. The ship had been scheduled to dock at 10 am.

Crew members said the tanker sank 30 minutes after it was hit by three large explosions.

The ship's captain told the website VnExpress. com that the tanker, with a crew of 15, was carrying 1.8 million litres of crude oil and 10,000 litres of diesel.

The captain said the three missing crew members were caught by an explosion as they attempted to hoist the ship's anchors and were thrown into the water. The other 12 crew members had already put on life jackets and abandoned ship.

Provincial authorities have reportedly sent forces to prevent the oil slick from spreading.(dpa)