BOSASSO (Somalia) - A SAUDI supertanker hijacked by pirates with a US$100 million (S$152.6 million) oil cargo in the largest ever such seizure has reached the coast of north Somalia, a regional maritime group said on Tuesday.

He was referring to a remote coastal village used by Somali pirates who have been terrorising ships in the Gulf of Aden and Indian Ocean this year. They have driven up insurance costs, forced some firms to go round South Africa instead of through the Suez Canal, and secured millions of dollars in ransoms.

The capture of Sirius Star 450 nautical miles (833.4 kilometres) south-east of Kenya's Mombasa port, and way beyond the Gulf of Aden where most attacks have taken place this year, is their boldest strike.

The seizure was carried out despite an international naval response, including from the Nato alliance and European Union, to protect one of the world's busiest shipping areas.

'The world has never seen anything like this', added Mr Mwangura, whose Mombasa-based group has been monitoring piracy for years. He said the pirates would probably keep the Sirius about eight miles off Eyl, which is heavily protected.

Mr Mwangura, who bases information on shipping groups in the region plus relatives of both crew and pirates, said he believed a hijacked Nigerian tug was used as a 'mothership'.

'The supertanker was full loaded, so it was probably low in the water and not that difficult to board', he said, adding that the pirates probably used a ladder or hooked a rope to the side.

Normally, the increasingly well-armed and sophisticated Somali pirates use speedboats to carry out the attacks, with the mothership as a base for their operations.

International crew
Mr Mwangura said he believed the Somali pirates might have had help from others, possibly Nigerians and Yemenis, for this attack, given its distance from Somalia and the scale of the attack. However, he said he had no firm evidence of that.

The seizure of the Sirius, which is three times the size of an aircraft carrier, follows another spectacular strike earlier this year by the pirates when they captured a Ukrainian ship carrying 33 tanks and other military equipment.

They are still holding that vessel, and as about a dozen other hijacked ships, under close surveillance by US and other warships in the area.

Given that the pirates are in most cases holding crews hostage, and are well-armed with grenades, machineguns and rocket-launchers, foreign forces in the area are steering clear of direct attacks. Ship owners are negotiating ransoms.

The Sirius held as much as 2 million barrels of oil, more than a quarter of Saudi Arabia's daily exports.

The hijacking helped lift global oil prices over US$1 to more than US$58 a barrel, although they later lost some gains.

Admiral Mike Mullen, chairman of the US Joint Chiefs of Staff, said military intervention would be complicated by hostages and ransom demands.

'I'm stunned by the range of it', said Adm Mullen.

The Sirius had been heading for the United States via the Cape of Good Hope at the southern tip of Africa, skirting the continent instead of heading through the Suez. It had 25 crew from Croatia, Britain, the Philippines, Poland and Saudi Arabia.

Chaos onshore in Somalia, where Islamist forces are fighting a Western-backed government, has spawned this year's upsurge in piracy. The Islamists, who are close to the capital Mogadishu, say that if they take control they will stop piracy as they did during a brief, six-month rule of south Somalia in 2006.

Analysts say, however, that all sides in the Somali conflict are benefiting from the spoils of piracy. International Maritime Bureau, a piracy watchdog, said there had been 92 attacks off Somalia this year and 36 of the ships had been hijacked.

The Sirius is Liberian-flagged and owned and operated by state oil giant Saudi Aramco's shipping unit Vela International. -- REUTERS