KUALA LUMPUR - CHINESE sailors backed up by a coalition warship and helicopters foiled a pirate attack in a dramatic high-seas encounter off the coast of Somalia, a maritime watchdog said on Wednesday.

The band of pirates boarded the Chinese-owned vessel 'Zhenhua 4' but the sailors prevented them from invading their crew accommodation for several hours - enough time to seek help from the coalition forces.

'I'm actually very surprised that the crew managed to hold back the pirates. I don't know how they did it, but they did it,' said Noel Choong, head of the International Maritime Bureau piracy reporting centre in Kuala Lumpur.

'Because of this action, the military helicopters came and they managed to chase the pirates away. The pirates on board eventually left the ship and the master is proceeding on his course,' he told AFP.

Mr Choong said the alert was raised on Wednesday after the IMB received a distress call, setting off a chain of communications with the ship owners and coalition forces patrolling the pirate-infested region.

A warship was dispatched to the area, and the IMB sent the stricken Chinese vessel coordinates of a meeting point so the crew could reach assistance more quickly.

'It's good news but it took several hours for all this to happen,' Mr Choong said.

'So everyone is safe but it was a real drama. We were actively involved for several hours, we were calling here and calling there.' Mr Choong said he could not confirm the number of sailors on board, although Chinese state media said there were 30.

The official news Xinhua agency had reported that the sailors were missing after the attack in the Gulf of Aden which occurred at 0443 GMT (12.43pm Singapore time). -- AFP