MOGADISHU - A British couple hijacked by pirates as they slept aboard their boat while on an Indian Ocean yachting holiday were Thursday taken to another captured ship anchored off the Somali coast.

Paul Chandler, 58, told Britain's ITV News channel that he and his 55-year-old wife Rachel were snatched on Friday last week and described how the pirates took everything of value on his yacht, the Lynn Rival.

The line was cut before he was able to answer a question on how the pirates were treating them.

"I was off watch. I was asleep and men with guns came aboard," he said, adding that the pirates had not yet made an official ransom demand.

The couple were sailing from the Seychelles to Tanzania across Indian Ocean waters when they were captured and forced to sail towards Somalia.

"They (the pirates) kept asking for money and took everything of value on the boat," he said, adding that they had been transferred to a Singaporean container ship called MV Kota Wajar that the pirates seized earlier this month.

Chandler's brother-in-law Stephen Collett confirmed it was his voice heard during the call and the hostage's brief account matched information provided by the pirates themselves.

"The hostages were picked up from their yacht and are now on board one of the other ships we were holding off Harardhere," Abdi Yare, a local pirate leader, had told AFP by phone earlier.

Harardhere is one of Somalia's main piracy hubs and lies some 300 kilometres north of the capital Mogadishu.

The British ministry of defence confirmed that the abandoned yacht of the Chandlers had been sighted.

"The MoD can confirm that during counter-piracy operations overnight a Royal Navy ship encountered the yacht owned by Paul and Rachel Chandler. It was found in international waters," the ministry said in a statement.

"Paul and Rachel Chandler were not on board the yacht and we do not have any reason to believe they have been harmed."

Yare and other members of the Harardhere pirate groups said no decision had yet been made on whether to continue holding the couple off-shore or to transfer them to land.

Somalia's marauding sea bandits continued their rampage around the Seychelles and also seized a Thailand-flagged trawler Thursday, bringing to nine the total number of ships hijacked off Somalia.

The European Union's anti-piracy naval force, NAVFOR, said the fishing vessel Thai Union 3 came under attack from two skiffs about 200 nautical miles north of the Seychelles archipelago.

An EU navy patrol aircraft "made visual contact with the fishing vessel and confirmed that pirates were on board. Skiffs used by pirates have been sighted onboard the fishing vessel," a statement said.

The Seychelles coastguard said in a statement that the crew consisted of 21 Russians, two Ghanaians and two Filipinos.

While most of the more than 100 ships hijacked since the beginning of 2008 have been merchant or fishing vessels, pirates have also seized more vulnerable targets such as private yachts on several occasions.

Some of the most high-profile cases include the hijacking of the Tanit earlier this year, which ended with French commandos shooting dead two pirates and a hostage in a bid to rescue him, his wife and young child.

Somali pirates, who have launched almost daily attacks near the Seychelles since monsoon winds dropped a month ago, currently hold a total of nine ships and around 200 crew.