China is building an aircraft carrier, a top Chinese military official has confirmed in the first official acknowledgement of the ship's existence.

"The aircraft carrier is being built, but has not been completed," Chen Bingde, Chief of General Staff of the People's Liberation Army, said during an interview with the Hong Kong Commercial Newspaper. He declined to give any more details on the ship.

The newspaper yesterday quoted Qi Jianguo, Chen's deputy, as saying the aircraft carrier, China's first, would never sail into other countries' territorial waters.

Qi said such a scenario was "impossible" in accordance with China's defensive military strategy.

He told the newspaper that all the major countries in the world, including other permanent member states of the United Nations Security Council, had their own aircraft carriers and China should also go through that phase. China was facing great threats and pressures from the seas around the country, Qi said, a situation that was more complicated than that facing other world powers.

In February, Britain rejected a 5 million pound (US$8.23 million) bid for a junked aircraft carrier from a UK-based Chinese businessman, Lam Kin-bong, who said at the time that he was planning to turn the warship into a floating international school off the coast of Guangdong Province.

Lam, who moved from south China's Guangdong to London nearly 20 years ago, was running a restaurant chain in Birmingham.

The British authorities may have suspected that the Chinese government or military authority was behind the bid, Hong Kong-based Wen Wei Po reported earlier.

The HMS Invincible, decommissioned in 2005, could carry 22 warplanes and nearly 1,100 sailors.