Suspected Somali pirates have hijacked a merchant ship with 27 crew off the sultanate of Oman, the head of a regional maritime group and the European Union Naval Force of Somalia said on Saturday.

Andrew Mwangura of the Kenyan-based East African Seafarers Assistance Programme said the pirates had seized the Thai-flagged vessel early on Saturday while sailing from the United Arab Emirates.

'Reports reaching Mombasa indicate that early this morning pirates sized MV Thor Nexus some 350 nautical miles east of Salalah, Oman,' Mwangura said in a statement.

Mwangura added that it was likely the pirates were Somalis. 'They are the ones known to do this,' he told Reuters by phone.

The European Union Naval Force (EU Navfor) said in a statement the general cargo ship has a weight of 20,377 tonnes, and put the area of the hijacking at 450 nautical miles north east of Socotra island in the Indian Ocean.

Mwangura said the vessel was heading to Bangladesh, not Pakistan as reported earlier. EU Navfor also gave as its destination as Bangladesh. 'No details of the attack are known at this stage,' EU Navfor said.

Pirates are making tens of millions of dollars in ransoms from seizing merchant ships in the Indian Ocean and the Gulf of Aden, despite efforts by foreign navies to clamp down on such attacks.

The hijackings have driven up insurance premiums and forced ships to take longer, costlier routes to avoid piracy hot spots.

Industry officials say marine insurers in London's insurance market have widened the stretch of waterways deemed at high risk from Somali pirates as the armed gangs strike further out at sea.-Reuters