AFP

New Delhi, Nov 26: Indian Navy said on Wednesday that a ship it attacked and sank in the Gulf of Aden was hostile, after a maritime watchdog said the vessel was a Thai fishing trawler and not a pirate ship.

"The vessel was similar in description to what was mentioned in various piracy bulletins," an Indian Navy spokesman, Commander Nirad Sinha said.

"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... Pirates were seen roaming on the deck with rocket-propelled grenade launchers."

He said the Indian Navy only opened fire after being fired upon, and that "exploding ammunition was also seen" on the target.

The Indian Navy won international praise 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, said on Wednesday the vessel attacked was a Thai-operated fishing boat which had been seized by pirates off Yemen on November 18.

Another Indian Navy official, speaking on condition he not be named, dismissed the IMB's account.

"Photographs of the attack and sinking of the vessel show a huge fireball. This shows there was ammunition carried on board, otherwise how could it have been such a great explosion?" the Navy official said. "If it was a fishing trawler, it could not have resulted in such a huge explosion."

An Indian defence ministry official said: "They tried to attack us and our actions were in defence of that -- whichever the ship was."

"It was a pirate vessel in international waters and its stance was aggressive," the official said.