"The defence and security forces on March 17 freed seven Chinese nationals taken hostage in Cameroon's territorial waters ... by individuals (who have) not yet been identified," the presidency chief of staff Laurent Esso, said in a statement.

The operation was carried out on orders from President Paul Biya, the statement read on state radio said without any details about how it was conducted or whether there were any victims.

Quoted by China's Xinhua news agency, China's ambassador, Xue Jinwei, said on Wednesday the men were freed with help from the Cameroonian authorities.

The seven fishermen were working for a private Chinese company when they were kidnapped on March 12 off the Bakassi peninsula, which is rich in fish stocks and believed to have substantial oil reserves.

Their kidnapping was claimed by a hitherto unknown group that called itself Africa Marine Commando.

Several groups, mostly armed, are active in the Bakassi peninsula, which was handed over to Cameroon by Nigeria in August 2008 under an international court settlement of a border dispute. Elite Cameroonian troops patrol the peninsula.

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