UPDATE: Pirates Ransom Saudi Vessel; Three More Ships Seized

Pirates demanded a ransom for an oil- laden Saudi supertanker amid reports three other merchant vessels have been hijacked in one of the worst spates of attacks in the Gulf of Aden and off the East African coast.

``Negotiators are onboard the ship and on land,'' a man identifying himself as Farah Abd Jameh, a member of the group that hijacked the Saudi tanker, said in an audio tape aired by Dubai-based Al Jazeera television. ``Once they agree on the ransom, it will be taken in cash to the oil tanker.''

Saudi Arabia's state-owned shipping line, Vela International Marine Ltd., yesterday said it had set up negotiation teams to free the tanker, Sirius Star, and its crew of 25, seized on Nov. 15 about 420 nautical miles (833 kilometers) off Somalia. The vessel is carrying more than 2 million barrels of crude valued at $110 million.

A large, Saudi-owned crude oil carrier has been captured by pirates in the Arabian Sea, according to the US Navy.

The tanker was taken on Saturday while it was some 450 nautical miles south-east of the port of Mombasa, and is now approaching the Somali port of Eyl.

The Sirius Star is carrying some 25 international crew members including two Britons.

An earlier Saudi TV report said the vessel had been freed.

The report on the al-Arabyia channel quoted an unnamed "official" Saudi source.

But the US Navy's 5th Fleet later told news agencies that the ship was "nearing an anchorage point" at Eyl, a port often used by pirates in the Somali region of Puntland.

A BBC correspondent in Mombasa reports that this is the third tanker to have been hijacked in the region.

It is also the largest vessel so far to come under attack by pirates in the area, the US Navy told the BBC.

The location is unusual and the capture marks a fundamental shift in tactics, the navy added.

Attacks on shipping off the Horn of Africa and Kenya by pirates, who are mostly Somali, prompted foreign navies to send warships to the area this year.

Figures from the International Maritime Bureau show that attacks in the area - the Gulf of Aden and the Indian Ocean off the African coast - have made up one-third of all piracy incidents worldwide in 2008.

In the first nine months of the year 63 incidents were reported.

As of 30 September, 12 vessels remained captive and under negotiation with more than 250 crew being held hostage.

Pirates remain active and regularly strike in the region. In the past week alone

• A Russian warship in the Gulf of Aden drove off pirates who tried to capture the Saudi Arabian merchant ship Rabih

• Pirates hijacked a Japanese cargo ship off Somalia

• A Chinese fishing boat was seized off the Kenyan coast

• A Turkish ship transporting chemicals to India was hijacked off Yemen

• The UK's Royal Navy shot dead two suspected pirates attacking a Danish cargo-ship off the coast of Yemen.