China's aircraft carrier battle group carried out a full drill in first-degree combat readiness on Saturday, the highest level of a four-tier defense readiness protocol, the Defense Ministry said on Monday.

The drill was to strengthen coordination among the fleet's vessels and planes, and improve the skills of the crew and pilots in different marine regions under real combat situations, said Gao Zhaorui, the fleet's chief of staff.

The fleet includes the CNS Liaoning, China's first aircraft carrier; guided-missile destroyers CNS Jinan and CNS Yinchuan; and guided-missile frigate CNS Yantai. The group set out from Qingdao, Shandong province, on June 25 for routine trans-regional exercises.