Pirates have taken control of a supertanker off the east coast of Africa that is carrying a full load of two million barrels of oil - over one-quarter of Saudi Arabia's daily output worth some US$178 million.

Owned by the Saudi company Aramco, the Sirius Star was bound for the United States via the Cape of Good Hope at the southern tip of Africa when it was captured on Saturday some 450 nautical miles south-east of Kenyan port city of Mombasa. It is reportedly heading for the Somali port of Eyl.

US Navy spokesman Lt Nathan Christensen says it is the largest ship they have seen pirated. The vessel is three times the size of a US aircraft carrier.

The BBC says the international crew of 25, from Britain, Croatia, the Philippines, Poland and Saudi Arabia, is said to be safe.

The International Maritime Bureau (IMB) says one-third of all piracy attacks worldwide in 2008 occurred in the marine region from the Gulf of Aden and the Indian Ocean off the African coast.

IMB figures show there was 63 reported piracy incidents in the first nine months of the year, with 12 vessels still captive and under negotiation with more than 250 crew being held hostage as at September 30.

© NewsRoom 2008