NAIROBI - A Saudi supertanker hijacked by pirates with a $100 million oil cargo in the largest ever such seizure has reached the coast of north Somalia, a regional maritime group said on Tuesday.

"Some people are saying they have spotted a huge vessel off Eyl. It must be the supertanker," Andrew Mwangura, coordinator of the East African Seafarers' Association, told Reuters, referring to a remote coastal village used by Somali pirates.

Sirius Star, which is owned by Saudi Aramco, carried 25 crew members from Croatia, Britain, Philippines, Poland and Saudi Arabia, according to a US Navy statement. The 318,000-ton vessel, launched earlier this year, is flagged in Liberia and operated by Vela International.

The capture of the Sirius Star 450 nautical miles southeast of Kenya's Mombasa port is the furthest and boldest strike to date by Somali pirates.

The seizure was carried out despite an international naval response to protect the busy shipping lanes off Somalia in the Gulf of Aden and the Indian Ocean.

"The world has never seen anything like this," added Mwangura, whose group has been monitoring piracy off Somalia for years. He said the pirates would probably keep the Sirius about eight miles off Eyl.

Mwangura, who bases his information on shipping organizations in the region plus relatives of both crew and pirates, said he believed a hijacked Nigerian tugboat was used as a "mother-ship" in Monday's extraordinary capture.

"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 mother ship as a base for their operations.

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.

Pinoys on hijacked carrier Chemstar Venus safe

Twenty-three seafarers including 18 Filipinos on board a hijacked chemical carrier in the Gulf of Aden are safe and have not been harmed, a Department of Foreign Affairs official said Tuesday.

Citing a report from the Philippine Embassy in Nairobi, Executive Director Cresente Relacion of the Office of the Undersecretary for Migrant Workers Affairs said the Japan-owned Panama-flagged chemical carrier M/C Chemstar Venus was hijacked by suspected Somali pirates last November 16.

“DFA has instructed Philippine Embassies in Nairobi and Tokyo to coordinate with shipowners and international maritime authorities on efforts to secure safe release of crew and vessel,” Relacion said in a text message.

Andrew Mwangura who runs the Kenya chapter of the Seafarers Assistance Programme earlier said Somali pirates attacked the 20,000-ton Chemstar Venus last Saturday.

The International Maritime Bureau has reported that at least 83 ships have been attacked off Somalia since January, of which 33 were hijacked. Of those, 12 vessels and more than 200 crew were still in the hands of pirates.

Last week, the European Union started a security operation off the coast of Somalia, north of Kenya, to combat growing acts of piracy and protect ships carrying aid agency deliveries. It is the EU's first-ever naval mission.

Dubbed Operation Atlanta, the mission, endorsed by the bloc's defence ministers at talks in Brussels, is being led by Britain, with its headquarters in Northwood, near London.

Pirates are well organised in the area where Somalia's northeastern tip juts into the Indian Ocean, preying on a key maritime route leading to the Suez Canal through which an estimated 30 percent of the world's oil transits.

They operate high-powered speedboats and are heavily armed, sometimes holding ships for weeks until they are released for large ransoms paid by governments or owners.

NATO warships, along with ships and aircraft from several other nations have been deployed in the region to protect commercial shipping.  With reports from Reuters and Agence France-Presse