A J-15 fighter jet is on a training session aboard aircraft carrier Liaoning. [Photo by Li Tang/For China Daily]

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.

On Saturday afternoon, hundreds of servicemen and women went into action. At the same time, several groups of armed J-15 carrier-borne fighter jets took off into the sky.

After the jets completed their objectives and returned to the carrier, personnel flocked to the planes to begin maintenance and refueling.

Xu Ying, a senior pilot, said it was his first time participating in a trans-regional drill. "Taking off in challenging sea and weather conditions really puts all the pilot's abilities to the test," he was quoted as saying in a ministry news release.

"After the drill, we pilots feel our piloting skills, mental fortitude and combat capabilities have improved. These skills will help us complete more complicated missions in the future."

Completing the full flight routine, from preparation to landing, has improved the flight crew's overall skills and efficiency, said Xu Yinghong, the captain of the flight crew. They also found new ways to optimize the procedure to make it go more smoothly.

The commander of fleet, who was not named in the ministry news release, said the objectives of the drill were divided into three major parts - vessel maneuvering, flight and equipment testing.

Every vessel also had to follow the central order of the fleet command, and complete various complicated tasks, such as changing formation and target surveillance, as a cohesive group, he said.

The fleet will visit Hong Kong from Friday to Tuesday to celebrate the 20th anniversary of the People's Liberation Army Hong Kong Garrison, the garrison said in a statement.

The garrison assumed defense duties of the city on July 1, 1997, when its sovereignty was returned to China from the United Kingdom. It currently has about 6,000 personnel and is commanded by Lieutenant General Tan Benhong.

Sections of the carrier and warships will be open to the public for the first time throughout the weekend. Hong Kong residents will also have a chance to interact with officers and sailors from the fleet, the statement said.

The CNS Liaoning is a refitted Soviet-era vessel that was commissioned by the PLA Navy in 2012. China also launched its first domestically built aircraft carrier in April.

[email protected]