The BBC says Somali pirates have called the broadcaster to demand $7 million in return for releasing a British couple whose yacht was hijacked off the coast of Africa.

The BBC cited an unidentified caller as saying the size of the ransom was justified because NATO forces in the area had arrested Somali fishermen and destroyed their equipment.

Paul and Rachel Chandler have been moved from dry land at a coastal pirate haven and brought back to sea, a maritime expert told Fox News.

They were transferred back to one of two hijacked ships in control of the pirates — a Singaporean-flagged vessel or a Spanish fishing vessel being held off the Somali coast, according to Nick Davis, director of Anti-Piracy Maritime Security Solutions, which runs security crews in the Gulf of Aden.

SLIDESHOW: British Couple Kidnapped by Pirates

Davis told Fox News that elders in the coastal pirate lair of Hardaheere, where the British couple were held overnight, thought the presence of the couple was too dangerous for the town to manage.

Fox News communicated with an alleged pirate via satellite phone Thursday, who mentioned a ransom for the Chandlers’ release, which is now $7 million.

When asked by Fox News whether the couple was safe, the alleged pirate answered, "Yes."

The presumed pirates refused to answer other questions and would not let reporters speak to the Chandlers. The pirates were on the Kota Wajar cargo ship when Fox News reached them on the ship's satellite phone.

The Kota Wajar was hijacked by pirates earlier this month with 21 crew members on board.

On Thursday, Paul Chandler, 59, described to ITV News how armed Somali pirates kidnapped him and his wife as they slept aboard the yacht they were sailing in the Indian Ocean, Sky News reported.

Speaking by phone to the 24-hour U.K. news channel, Chandler said, "I was asleep and men with guns came aboard," Sky News reported.

The retired quantity surveyor and his economist wife Rachel, 55, disappeared while taking their vessel, the Lynn Rival, from the Seychelles towards Tanzania.

Chandler continued, "I was off watch. I was asleep and men with guns came aboard. It was on Friday last week at 2.30pm."

Before the phone call, the kidnapping and the couple's safety had not been verified.

Chandler's brother-in-law, Stephen Collett, confirmed that it was his voice which was heard during the call.

Fox News' Greg Palkot, Sky News and The Associated Press contributed to this report.

Click here to read more from Sky News.

Click here to read the full transcript of the phone call from The Times Online.