A man claiming to be the spokesman of pirates holding a Ukrainian ship laden with Russian tanks said they wanted $35 million to set it free.

As a Greek tanker reportedly became the latest victim of Somalian pirates, Ali Yare Abdulkadir said the men who seized the Ukrainian vessel Faina wanted to negotiate with the Kenyan government and would offload the small arms if that did not happen.

Abdulkadir, who was speaking by telephone to The Associated Press news agency, would not reveal his whereabouts, but said the cargo ship Faina was somewhere along Somalia’s northeastern coast.

He warned against any military action to release the ship, saying that anyone who tried “will be responsible for the consequences.”

On Friday the Russian Navy announced that it was sending the frigate Neustrashimy (Fearless) to the region in response to "the rise in pirate attacks, including against Russian citizens".

Three Russians are reportedly among the people on board the Ukranian vessel. Ukraine's foreign ministry said there were also 17 Ukrainian nationals and one Latvian aboard the Belize-flagged ship, which officials say is carrying 33 T-72 tanks, grenade-launchers and ammunition.

Captain Igor Dygalo, a Russian Navy spokesman, said the Neustrashimy had left the Baltic Sea port of Baltiisk a day before the hijacking to cooperate with other unspecified countries in anti-piracy efforts. But it was then ordered directly to the Somalia coast after Thursday’s attack. Its precise mission was unclear but Sergei Kuks, a spokesman for Russia’s Baltic Fleet, said it was premature to say they wold participate in an effort to free the hostages. The frigate is expected to take about a week to reach Somalia’s coast.

The Greek ship reportedly seized on Friday is a chemical tanker with 19 crew members .The tanker, carrying refined petroleum from Europe to the Middle East, was ambushed in the Gulf of Aden according to Noel Choong, head of the International Maritime Bureau’s piracy reporting centre based in Malaysia. The bureau acts as an international anti-piracy watchdog.

Mr Choong said the pirates chased and fired at the tanker before boarding it, bringing the number of attacks on ships off the coast of Somalia to 62 this year, or more than one every week. A total of 26 ships were hijacked, and 15 remain in the hands of pirates along with 300 crew members.

How many of those are aboard the Ukrainian Faina is unclear. The Russian news website Life.ru today posted a telephone conversation with a man who said he was Vladimir Nikolsky, the ship's first mate, and insisted on speaking in English at the behest of the pirates. He said there were 35 people on board, not 21 as reported by Ukrainian officials.

He said: "They are asking that we make contact with the owners about his money.”

Asked how much they were demanding, he replied: “I’m not sure, approximately - I cannot say the exact price. They would like to speak directly to our owner.”

The man said the Faina was anchored near the town of Hobyo and that two other apparently hijacked ships were nearby. Most of those on board were being kept in a single room "without free air", he added. Nobody had been injured, but the captain, Vladimir Kolobkov, was suffering from heatstroke and his condition was “not so good”.

It was unclear exactly when the conversation with the purported crewman took place. Speaking in imperfect English, he said he had recently spoken to the captain of what he said was a US Coast Guard ship, who asked about the situation aboard the Faina. “I tell him that everything in normal condition,” he said.

At the beginning of the posted audio report, the reporter asks a person answering a call if she can speak to a Russian on board. After a few barked words in an unfamiliar language, the man identified as Mr Nikolsky starts speaking. He explains that he has been ordered to speak only English “so that they understand”. At the end, when the reporter asks whether he sees a way out, Mr Nikolsky replies: “You are so clever that you are understanding everything; and switches to Russian, saying “kotiki, kotiki, kotiki" - part of the word for seals - an apparent reference to the possibility of an operation by special amphibious forces to rescue the hostages.

According to Ukrainian news agencies the ship’s operator is Tomex Team, a company based in the Black Sea port of Odessa. A person who answered the phone at the company’s office today declined to comment and refused to give his name.

Bogita Ongeri, a Kenyan Defence Department spokesman, said the Kenyan authorities had had no contact with the pirates and had not received any demands for ransom.

He said the Ukrainian vessel was seized in international waters in the Gulf of Aden, 200 nautical miles from the coast of the northeastern Somali region of Puntland. That is the distance that, in maritime law, marks the end of a country’s territorial waters.

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