Laden with its highly flammable cargo of benzene, the Golden Nori floats like a ticking bomb off the coast of Somalia. The pirates who have hijacked her are threatening to kill the crew if their $1 million (£490,000) ransom demand is not met, while two US warships train their cannon on the vessel.

The Panamanian-flagged ship is the 28th to be snatched by pirates this year as Somalia spirals further into anarchy.

Hundreds of thousands of people have fled Mogadishu, the capital, as clan militias and Islamic insurgents fight government forces. Aid vessels laden with food are escorted by French warships.

There is little effective government and pirates are able to operate freely, according to industry experts. Andrew Mwangura, head of the Kenya chapter of the Seafarers’ Assistance Programme, said: “When the Islamic Courts were in power for six months last year there was only one hijacking and they resolved it quickly. When the Ethiopian troops and the Transitional Federal Government threw them out at the start of the year the hijackings began again.”

The Golden Nori was on her way from Singapore to Israel with thousands of tonnes of chemicals when she was attacked by three pirate speedboats at the end of October. US warships picked up her distress calls and fired on the gunmen, sinking two of their boats. Now the warships have isolated the Japanese-owned Golden Nori close to Bossasso, capital of the autonomous province of Puntland, preventing the pirates picking up supplies.

Mr Mwangura said: “If the owner is not co-operative or if they think they are in danger — with the Americans lurking — anything could happen.”

The World Food Programme, which is trying to get emergency help to 1.2 million people in the country, said that shipping corridors were vital. “With the quantities that we have to move it is simply not feasible to use overland routes,” it said.

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