A vessel destroyed by the Indian navy in the Gulf of Aden was not a pirate mothership, but a Thai fishing boat with 16 crew that had been hijacked hours earlier.

The Indian navy won international praise after the Nov 18 battle for taking on the Somali pirates who have turned the vital Suez Canal trade route into the world's most dangerous waterway.

But Noel Choong, head of the International Maritime Bureau (IMB) piracy reporting centre in Malaysia, said the boat it blasted to pieces was actually a Thai-operated fishing trawler which had been seized by pirates off Yemen.

"We can confirm that the incident has taken place. One Thai crew member died during the attack by the Indian navy, on the same day the vessel was hijacked by Somali pirates," he said.

Choong said that one Cambodian crewman was rescued by passing fishermen four days later, but 14 other crew on the Kiribati-registered vessel are still missing.

India's navy defended itself, saying that the vessel it fired on had been hostile and that it had acted in self-defence.

"The Indian navy ship asked them to stop for investigation on repeated calls. The vessel responded by saying it would blow up the Indian ship," navy spokesman Commander Nirad Sinha said in New Delhi.

"Pirates were seen roaming on the deck with rocket-propelled grenade launchers," he said, adding that the Indian navy only opened fire after being fired upon.

Choong said that photographs of the Thai vessel had been sent out to the navies of nations taking part in joint patrols of the pirate-infested waters.

"The Indian navy may have not received this information as they are not part of the coalition forces and we have no direct link with them," he said.

Deep sea trawler hijacked earlier

The owners of the downed boat, Thai-based Sirichai Fisheries, confirmed that the deep sea trawler Ekawatnava 5 had been destroyed, and said the crew were tied up when it came under fire from the INS Tabar.

"The ship was hijacked early in the day and was sunk in the evening," its managing director Wicharn Sirchaiekawat told AFP in Bangkok.

"Based on the surviving Cambodian crew member's account, all of them were tied up except two - the captain and translator - during the attack."

Wicharn said the Thai foreign ministry had summoned the Indian ambassador to Bangkok to make a formal complaint.

"We want to know the details - why it was sunk and why the Indian navy did not rescue the crew," he said.

Choong said that naval ships operating independently in the region should make efforts to obtain information on hijacked vessels and that they should link up with coalition forces to avoid more "tragic" incidents.

The IMB has declared the piracy problem is "out of control" as the bandits operate with impunity out of bases in Somalia, which has no central government.

The issue shot into the headlines with the seizure of a Saudi supertanker 11 days ago. The pirates are demanding a US$25 million ransom have called for negotiations to be stepped up ahead of a Nov 30 deadline.

Mohammed Said, the leader of the group which captured the Sirius Star, which is carrying two million barrels of crude oil, said protracted talks were not helping them, the ship's owners or the crew.

"We are urging the owners of the Saudi tanker to have an honest dialogue in order to end the crisis," he said in Mogadishu on Tuesday.

"Too much delay is not good for us and for the owners of the tanker and the crew as well. We are not threatening them but we are urging them to be honest."

96 ships have been attacked

Two British crew members apparentedly backed up Said's claim that the hostages were being treated well.

"Everything is OK, we've got no mistreatment or anything, we're being treated quite well," Peter French, the chief engineer on the Sirius Star, told ITV News television by telephone.

"Hopefully we are going to get some more phone calls to our families soon. Our families don't have too much to worry about at the moment," he said.

It was unclear whether the pirates were present during the interview.

The international community has been rushing naval ships to the region in a bid to combat piracy, vowing tough action against a surge in attacks which is threatening major disruptions in international trade.

The IMB said 96 ships have been attacked so far this year off Somalia and in the Gulf of Aden, with 39 hijacked and 15 still being held with more than 300 crew aboard.