Suspected pirates have hijacked a Thai cargo ship in the Gulf of Aden off the Somali coast, a regional maritime official confirmed on Thursday. Andrew Mwangura, the East Africa Coordinator of Seafarers Assistance Program (SAP), said the MV Thor Star, was hijacked on Thursday with unknown number of crew members on board.

"The Thai ship was hijacked some 200 nautical miles north of Seychelles.There are still conflicting reports as to where the vessel was heading to and the nationalities of the crew members onboard," Mwangura told Xinhua by telephone from Mombasa.

The Thai-flagged ship is owned by Bangkok-based Thoresen Thai Agencies.

Earlier reports said the Somali pirates had seized a Thai fishing boat.

Somali pirates have seized dozens of ships over the last two years, taking in tens of millions of dollars in ransom money. The pirates are believed to be holding seven ships in all.

The Somali pirates, who come from specific regions and clans far away from the war-ravaged capital, have been challenging the coalition of warships patrolling the world's most dangerous waters to end the menace.

An estimated 25,000 ships annually cruise the Gulf of Aden, off Somalia's northern coast. Over 10 ships and 200 crew members are still held by Somali pirates. The Gulf of Aden, off the northern coast of Somalia, has the highest risk of piracy in the world. About 25,000 ships use the channel south of Yemen, between the Red Sea and the Arabian Sea.