China is making use of an obsolete aircraft carrier that was bought from Ukraine and is being refitted for scientific research and training purposes, a top military spokesman said on Wednesday.

The undated photo released by Xinhua News Agency on Wednesday shows the refurbished aircraft carrier which the Defense Ministry said will be used for research and training. [Xinhua]

"The warship has no problem with sailing since it has been docked in the sea, and the time for its maiden experimental voyage depends on the schedule of the refit," Defense Ministry spokesman Geng Yansheng said, referring to the Varyag in the northeastern port of Dalian.

The pursuit of an aircraft carrier program would not change the navy's strategy of inshore defense, he said at a news briefing in Beijing.

"Training for carrier-borne aircraft pilots is also in progress," Geng said.

He did not specify who would be named the Varyag's commander. The official China Defense Newspaper earlier quoted media reports as saying Li Xiaoyan, 50, and Bai Yaoping, 49, were widely seen as top candidates for the post.

Li and Bai are both 1990 graduates of the Chinese military's first course - a three-year program, and the only one so far - to train aircraft carrier captains.

Geng's announcement came days after an article in the Study Times, the official newspaper of the Central Party School of the Communist Party of China, said the Varyag may soon start sea trials.

The article on Monday referred to the carrier as "China's first aircraft carrier training vessel, Shilang". Shi Lang was a 17th century admiral who reclaimed Taiwan for the Qing Dynasty (1644-1911).

Xinhua News Agency, though, said on Wednesday that the warship is still unnamed.

It is set to receive final adjustments at a shipyard in Dalian "before embarking on its maiden voyage", Xinhua said.

The ex-Soviet Varyag, which remained incomplete when the Soviet Union collapsed in 1991, was bought for $20 million in 1998. Ukraine disarmed it and removed its engines before selling the craft to China. The vessel, delivered in 2002, has been undergoing refitting work at Dalian since 2005.

China is the last permanent member of the United Nations Security Council to get an aircraft carrier. Among the other four, the US boasts 11 and the UK, France and Russia each has one in operation.

In Asia, India and Thailand each bought and commissioned an aircraft carrier - in the late 1980s and 1990s, respectively.

"China will inevitably start far behind India's level of expertise in actual carrier aviation and operation," Andrew S. Erickson and Andrew R. Wilson, professors of strategy at the US Naval War College, wrote in 2006 in the Naval War College Review.