Two carrier strike groups of the People's Liberation Army Navy have recently conducted a joint combat exercise in the South China Sea, according to the Navy.

The operation took place in the middle of a long-distance exercise made by the CNS Liaoning aircraft carrier and its strike group that sailed across the Yellow, East China and South China seas from September to October, the Navy said in a brief news release.

After the Liaoning group arrived in the South China Sea, it was joined by another carrier strike group led by the CNS Shandong.

It marked the first time that China's two carrier strike groups took part in a same exercise and was intended to hone the joint operation capability of the two groups' personnel, according to the release.

The Liaoning group has returned to its homeport in Qingdao, Shandong province, the Navy noted without disclosing the Shandong group's whereabouts.

At a news conference in Beijing on Thursday afternoon, Senior Colonel Zhang Xiaogang, a spokesman for the Defense Ministry, said the two-carrier exercise was part of the Navy's annual training plan and aimed at improving the carrier strike groups' systematic combat strength.

Currently, the Navy operates two aircraft carriers — the Liaoning and the Shandong. Both have a standard displacement of around 50,000 tons and a conventional propulsion system, and they use a ski jump method for launching fixed-wing aircraft.

The country has built a third aircraft carrier — the CNS Fujian, which displaces more than 80,000 metric tons of water and uses an electromagnetic launch system, or electromagnetic catapult, to launch fixed-wing aircraft.

The new carrier has become the largest and mightiest warship any Asian nation has ever built, as well as the world's biggest non-US aircraft carrier. It is now in the sea trial stage and is expected to be commissioned in the near future.