Beijing - Pirates off the coast of Somalia have seized a Chinese fishing boat and 24 crew including Vietnamese, Philippine and Japanese citizens, Chinese state media reported on Friday.

The Chinese vessel was held off the coast of the southern Somali port of Kismanyu late Thursday, the government's official Xinhua news agency reported from Mogadishu, the Somali capital.

The agency quoted an unidentified pirate leader as saying on the local Shabelle radio station in Mogadishu that the 24 crew were all "fine."

The pirate leader claimed that he seized the vessel 30 miles (48.2 kilometres) off Kismanyu because it was fishing in Somali territorial waters and said the crew would be "put before the law and punished accordingly."

But the agency quoted a source with the Chinese Ministry of Transport as saying the ship, the Tianyu No 8, was fishing off the Kenyan coast when it was seized.

The pirates had forced the crew to sail towards the coast of southern Somalia, the Chinese source said.

The ship is owned by the Tianjin Ocean Fishing Company and carried a crew of 15 Chinese, four Vietnamese, three Philippine, one Japanese and one Taiwanese.

The pirates had not made any demands for the release of the ship, saying they would announce their demands "at a later time," the agency said.

Sea areas off Somalia have become notorious for piracy in recent years, prompting the deployment of international naval vessels.

Two suspected Somali pirates were shot and killed by the crew of a British navy frigate in the Gulf of Aden on Tuesday, the Ministry of Defence in London said.

A firefight occurred when crew of the Royal Navy ship HMS Cumberland dispatched sailors on boats to surround and board a pirate dhow that had attempted earlier to seize a Danish vessel, the ministry said in a statement late Wednesday, stressing that the killings had been in self-defence.

Pirates have hijacked 30 ships this year in the Gulf of Aden in the Arabian Sea between Yemen and Somalia, one of the world's main shipping routes, demanding high sums of ransom from the owners of countries of origin. (dpa)