Attacks by pirates off the coast of Somalia have fiercely intensified, with five vessels reportedly hijacked in the past week, including Saudi-owned supertanker Sirius Star, the largest vessel ever seized at sea.

Yesterday, a Hong Kong-flagged cargo ship was confirmed to have been hijacked in the Gulf of Aden near the coast of Yemen.

Andrew Mwangura, the East African Coordinator of the Seafarer Assistance Program, said the Delight, operated by an Iranian company and loaded with 26,000 tons of wheat, was bound for the Iranian port of Bandar Abbas when it was hijacked.

He said the fate of the crew or its cargo was not known, adding the ship was likely sailing toward an anchorage site off the Somali coast.

The Sirius Star, with a capacity of 2 million barrels of crude oil, was hijacked by Somali pirates Saturday, some 450 miles (725 kilometers) off the Kenyan port of Mombasa.

The supertanker, along with its international crew of 25, has dropped anchor off the Somali port of Harardhere, where a Ukrainian ship loaded with weapons is also being held since being captured in September, regional authorities told Xinhua.

The hijacking of the supertanker was shocking because it highlighted the vulnerability of even very large ships and pointed to widening ambitions and capabilities among ransom-hungry pirates.

Also over the weekend, a Japanese cargo ship carrying 23 crew members, among them five Koreans and 18 Filipinos, was confirmed hijacked by armed gunmen off the coast of Somalia.

Today, a Chinese fishing vessel was hijacked by pirates armed with grenade launchers and automatic weapons off the coast of Kenya and is being held off the southern Somali port city of Kismanyu.

The 24 crew aboard the abducted ship owned by the Tianjin Ocean Fishing Company include 16 Chinese, among them one from China's Taiwan province, one Japanese, three Filipinos and four Vietnamese.

It is the first time that incidents of piracy, usually endemic off the northern and northeastern Somali coast, were reported off the southern coast of the country.

The attack came hours after a Russian-operated cargo ship off the coast of Somalia luckily escaped pirates who had attacked it with grenade launchers and machine guns.

Last Wednesday, a Turkish ship, with 14 crew and 4,500 tons of unspecified chemicals, was also reported to have been hijacked by pirates off the coast of Yemen. It was the second hijacking of a Turkish ship within the past month.

Pirates have been causing havoc in one of the world's most dangerous waters of the Somali coast, which connects Europe to Asia and the Middle East. They have taken millions of dollars in ransom, raised insurance costs and threatened humanitarian supplies.

The hijackings come just as international communities intensified their efforts to combat piracy off Somalia.

The European Union (EU) has recently agreed to deploy an air and naval force off the coast of Somalia to guard sea lanes against piracy. The EU's naval mission, to be in place by next month, is expected to protect vulnerable vessels off the Somali coast and help ensure the delivery of aid.

Ten EU nations have said they will contribute to the EU operation, which is expected to involve four to six ships at any given time, as well as several maritime surveillance aircraft. It will have an initial one-year mandate.

Besides, NATO has already sent a fleet to protect food shipments to Somalia.

Meanwhile, the South Korean government also plans to combat piracy in the area by sending a 4,500-ton destroyer loaded with SM-2 Block IIIA missiles and other cutting-edge weaponry, as well as the Navy's Special Forces.