The Varyag was bought from Ukraine for $20 million in 1998. According to reports, it has been undergoing refitting work at a shipyard in the northeastern coastal city of Dalian since 2005.

"This has been a gigantic project and is virtually as complicated as building a brand-new aircraft carrier," an unidentified source with the military industry in Dalian was quoted as saying by the Kanwa Asian Defense magazine.

Just as the news came out that the Varyag will begin initial sea trials probably either late this month, in early August or later in the year, rumors arose saying that another aircraft carrier is being built in Shanghai.

In earlier June, the Hong Kong Commercial Daily quoted Chen as saying - during his flight to the US - that the construction of at least one aircraft carrier is "under way, and not finished yet".

Chen did not disclose on Monday how many aircraft carriers China plans to build.

He did acknowledge, though, that Beijing is developing the Dongfeng-21D, a ballistic missile with a maximum range of 2,700 kilometers and the ability to strike moving targets - including aircraft carriers - at sea.

"The missile is still undergoing experimental testing and will be used as a defensive weapon when it is successfully developed, not an offensive one," Chen said.

"It is a high-tech weapon and we face many difficulties in getting funding, advanced technologies and high-quality personnel, which are all underlying reasons why it is hard to develop this," he added.

The steam-powered Varyag is expected to serve primarily as a training vessel for pilots and deck crews. Speculation over what is going to be stationed on it has become more rampant in recent times. According to online leaks, the vehicles it carries may include the J-15 fighter, the JT-9 naval trainer and the Z-8 helicopter.

It is uncertain when the Varyag will be made operational and where it will be based.