The aircraft carrier Liaoning has conducted 10 sea trials since August 2011. Photos by Li Tang / for China Daily

ABOARD LIAONING AIRCRAFT CARRIER -- China's first aircraft carrier, the Liaoning, passed through the Taiwan Straits on Thursday morning on its way to a training mission in the South China Sea.

It took about 10 hours for the carrier and its four escort ships to get through the Straits separating the Chinese mainland and Taiwan.

The Liaoning entered the Taiwan Straits on Wednesday afternoon after it left its home port in Qingdao of East China's Shandong province on Tuesday for the South China Sea on a scientific and training mission.

It was escorted by two missile destroyers, the Shenyang and Shijiazhuang, and two missile frigates, the Yantai and Weifang.

During the voyage, the carrier has kept a high degree of vigilance against approaches from foreign warships and aircraft, according to Liaoning Captain Zhang Zheng.

This is the first time the carrier has conducted a cross-sea training voyage and passed through the Taiwan Straits since it was commissioned into the People's Liberation Army (PLA) Navy in September last year, according to Zhang.

It is also the fifth time this year that the vessel has been out to sea for experiments and training, the captain said, adding that all the year's operations have been conducted as scheduled.

Progress has been made regarding everything from integration of the carrier and carrier-borne aircraft to the skills of the carrier staff and aircraft pilots to the testing of equipment under complicated conditions, which has laid a firm foundation for proceeding trials, said Zhang.

The upcoming South China Sea engagement is a normal arrangement in the carrier's scheduled training, according to the PLA Navy.

The Liaoning is China's only aircraft carrier in operation. It was refitted based on an unfinished carrier of the former Soviet Union. The refitted carrier was delivered to the navy on Sept 25, 2012.