China has taken a major step toward commissioning its first aircraft carrier by largely completing the restoration of a derelict ship purchased from Ukraine, a news report said Wednesday.

The restoration includes all living and working compartments, engines, navigation systems and power-generating equipment, Hong Kong-based Kanwa Asian Defense magazine said. Additional work is still needed on the elevator and flight deck, it said, but it was unclear when the restoration would be completed.

The U.S. Department of Defense has said it expects the ship to be relaunched at any time as a platform for training pilots _ a major turning point in the military's wide-ranging modernization drive.

China bought the mothballed carrier in 1998 and towed the engine and rudderless ship to the northeastern port of Dalian for a complete refitting. Work on its internal systems took about four years, Kanwa said.

The complete restoration was intended to make the ship fully functional and to train technicians who will build China's future homemade carriers, according to the report.

"This has been a gigantic project and is virtually as complicated as building a brand-new aircraft carrier," Kanwa quoted an unidentified source with the Dalian region's military industry as saying.

The Varyag is a ski jump-style carrier with a displacement of about 55,000 tons, much smaller than the Japan-based U.S. carrier George Washington, which has a displacement of more than 100,000 tons.

China's secretive military has not commented on the aircraft carrier beyond vague statements that China will likely have such ships in future.

China is believed to be purchasing Russian Su-33 carrier-based fighters as well as adapting its own J-11 jets for carrier landings and takeoffs.

There were no other immediate reports to confirm Kanwa's account.

Kanwa is widely considered a highly reliable source. Last week, it reported extensively on the inaugural test flight of a prototype radar-evading Chinese stealth fighter.