BEIJING -- China's sole aircraft carrier has departed for its first-ever sea trials in the South China Sea, a mission likely to draw scrutiny amid Beijing's drive to assert its claims to those waters and their island groups.

The official Xinhua News Agency said the cruise aims to test the Liaoning's crew and equipment over long distances and a variety of sea conditions.

It said the ship was accompanied by two destroyers and two missile cruisers -- elements of a standard aircraft carrier battle group -- when it left its northern home port of Qingdao. The Liaoning has launched and recovered jet fighters but not yet been given its full complement of aircraft.

Since entering service last year, the carrier has conducted several rounds of sea trials in the relatively tranquil waters off China's northeast coast. State media reports Wednesday said the navy wanted to submit it to more trying conditions.

"It is hard to find an ideal area for the mission, except for the South China Sea," the China Daily newspaper quoted Maj. Gen. Yin Zhuo, a frequent spokesman on military affairs, as saying.

China says the South China Sea, its islands and potential mineral wealth belong to it, and has increasingly developed civilian and military outposts there and used its coast guard to confront the ships of other nations that also claim parts of the sea.

Yin said a cruise of up to two months was necessary to conduct proper sea trials, and would include the launching of fighters under difficult weather conditions.

Chinese navy ships on their way to the South China Sea have increasingly transited through the Miyako Strait in Japan's Okinawa island chain. While the strait is an international waterway, Japan's military pays close attention to the Chinese navy's activities in the area.

The Liaoning was bought from Ukraine more than a decade ago and extensively refurbished before entering service last year. At 57,000 tons, the ship is a little over half the size of the U.S. Navy's Nimitz class carriers.

China has described the carrier as an experimental platform but hasn't said whether it will play an active service role. The lengthy refurbishment was seen as a learning exercise for China's own future carriers, now believed to be under construction near Shanghai.