The pirates claiming to hold the British couple seized in the Indian Ocean threatened yesterday to “burn their bones” if a rescue were attempted.

The pirates were thought to be taking Paul Chandler, 58, and his wife Rachel, 55, to the Somali port of Haradheere and preparing to make ransom demands. A pirate commander in the town said that the couple and their 38ft yacht, Lynn Rival, were expected to arrive last night.

Speaking by telephone from Haradheere, a pirate called Mohamed Shakir told The Times that the capture of two people from Britain was “important for us because it is a wealthy country”.

Another pirate said that the couple would be killed if any attempt to free them were made before they and their captors reached land. “We are telling Britain that any bullet of our friends on the yacht will be big cries for the families of the two old people we hold,” a man who identified himself as Mohamed Hussein told Sky News in broken English.

A pirate called Hassan said: “We warn them any attack on us, this is a good advice for them, otherwise they will burn their two people’s bones. If warships surround us, we shall point our guns at the British tourists. They are old and we will take care of them — that is if we are not attacked.”

Mr and Mrs Chandler, from Tunbridge Wells, Kent, were last heard from on Friday night, a day after they left the Seychelles bound for Tanzania, when their distress beacon began transmitting.

About 30 warships from the European Union, Nato and the multinational Combined Task Force are deployed in the Gulf of Aden and along the Somali coast in an attempt to prevent the pirate attacks that have made the stretch of sea the most dangerous in the world.

On Tuesday evening a helicopter launched from an EU warship reported spotting “a sailing yacht in the line between the distress call and the Somali coastline”. But Lieutenant-Commander Daniel Auwermann said the poor light meant that it was impossible to be certain whether it was Lynn Rival. There have been no reported sightings since.

Speaking at Chatham House in London yesterday, Omar Sharmarke, the Somali Prime Minister, expressed his “sincere concern for the British couple who are missing presumed kidnapped”. Mr Sharmarke said that he had discussed the kidnapping with David Miliband, the Foreign Secretary. “I want to give my assurance to the family that my Government will do everything it can, within its resources, to find this couple and return them safely,” he said.

The Western-backed Government in Mogadishu is not in a position to do much. It is besieged by Islamist rebels and its authority extends no further than a few blocks of the capital. Haradheere is far beyond its control.

The release of hostages is usually accomplished by shipping companies or, in the case of yachts, governments. A German couple seized last year on board their yacht were held for 52 days and released only after a $600,000 (£370,000) ransom was reportedly paid by the German Government. Jürgen Kantner, 62, and his girlfriend, Sabine Merz, were subjected to mock executions, threats and hardship during their captivity in mountains.

An American captain was freed in April after US navy snipers killed the hostage-takers but when French commandos stormed a yacht taken by pirates that month one hostage was killed.

Additional reporting by our correspondent in Mogadishu

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