The owner of a Thai fishing trawler has said the Indian navy sank it off Somalia's coast last week after wrongly assuming it was a pirate "mother ship".
Wicharn Sirichaiekawat said the Indian frigate had attacked the Ekawat Nava 5 while it was being hijacked by pirates.
He said one of the crew had been found alive after six days in the Gulf of Aden, but that another 14 were missing.
The Indian navy has insisted the vessel fired in self-defence at a pirate ship which had been stacked with explosives.
Almost 40 ships have been seized by Somali pirates so far this year.
Earlier, the authorities in Yemen confirmed pirates had captured a cargo ship carrying building material off the country's coast. They said the pirates were demanding a ransom of $2m (£1.3m).
The latest incident came days after the Saudi oil tanker, Sirius Star, was hijacked. It was earlier moved further north up the Somali coast.
Mr Wicharn told reporters in Bangkok that the Ekawat Nava 5 had been headed from Oman to Yemen last Tuesday to deliver fishing equipment when it was approached by Somali pirates in two speed boats in the Gulf of Aden.
The pirates were in the process of boarding the vessel and seizing control when the Indian navy frigate, the INS Tabar, sailed into view and demanded it stop for investigation, he added.
"The sunken ship which the Indian navy claimed was a 'mother ship' of pirates was not the 'mother ship' at all," he said.
"The pirates wanted to take our ship to Somalia."
Mr Wicharn said he had learnt the fate of his trawler from a Cambodian crew member who had survived the INS Tabar's bombardment and had been rescued by a passing ship after six days adrift in the Indian Ocean.
The sailor was now recovering in a hospital in Yemen, he said.
Later, an Indian navy spokesman insisted that the Tabar had fired only upon a pirate "mother ship" which had threatened it.
"We fired in self-defence and in response to firing upon our vessel. It was a pirate vessel in the international waters and its stance was aggressive," Commodore Nirad Sinha told CNN.
Following last week's incident, the Indian navy said in a statement that the Tabar had spotted a pirate vessel while patrolling 285 nautical miles (530km) south-west of Salalah, Oman. It said those on board had been armed with guns and rocket-propelled grenade launchers.
When it demanded the vessel stop for investigation, the pirate ship had responded by threatening to "blow up the naval warship if it closed on her", the statement said.
The pirates then fired on the Tabar, after which the Indians retaliated and there was an explosion on the pirate vessel, which then sank, it added.
India is one of several countries currently patrolling the Gulf of Aden, one of the world's busiest shipping lanes. France, India, South Korea, Russia, Spain, the US and Nato also have a presence in the region.