A J-15 fighter takes off from the Liaoning on Friday during a fleet training exercise in the Yellow Sea. Mo Xiaoliang/CHINA DAILY

The CNS Liaoning aircraft carrier battle group has set off for the Western Pacific where it will take part in an open-sea exercise, a spokesman for the People's Liberation Army Navy has announced.

Senior Captain Liang Yang did not provide further details of the exercise on Saturday, but did say that it was part of the group's annual training schedule.

According to the PLA Navy, the group carried out "full-element" training in the East China Sea on Saturday, which mainly involved J-15 carrier-borne fighter jets.

The planes performed air tactical confrontation drills and air refueling operations, while ships conducted resupply training, the navy said.

"From the Bohai Sea to the Yellow Sea, and farther into the East China Sea, the carrier battle group ... has been exploring integrated, systematic and realistic training methods and performed 'full-element', joint exercises among the Liaoning, carrier-borne aviation units and escort ships," read a navy news release.

Footage broadcast by China Central Television showed Admiral Wu Shengli, commander of the PLA Navy, aboard the Liaoning as he oversaw the battle group's drills. It is not known whether Wu will remain aboard for the Western Pacific exercise.

The Japanese Defense Ministry said on Sunday it had spotted the Liaoning group on Sunday morning as the fleet was passing through the Miyako Strait toward the Western Pacific. The group consists of the aircraft carrier, three Type 052C and Type 052D guided missile destroyers and two Type 054A guided missile frigates, according to a Japanese news agency.

In mid-December, the Liaoning group carried out its first live-fire exercise in the Bohai Sea.

The carrier performed drills with destroyers and frigates, with scenarios including reconnaissance, aircraft interception, sea strikes and missile defense. Multiple groups of J-15s fired missiles at designated targets, the Chinese navy said.

Zhang Junshe, a senior researcher at the PLA Naval Military Studies Research Institute, said a long-distance training mission in the Western Pacific indicates that the Liaoning group has gained initial combat capability.

"This will expand the Navy's defense range and deter enemies' offensive operations," he said, adding that the major exercise will also test the group's logistics ability.

The PLA commissioned the CNS Liaoning in September 2012 in Dalian, Liaoning province.

Its battle group took shape in December 2013, when the carrier and several escort vessels, including two guided missile destroyers, two guided missile frigates and an attack submarine took part in a long-range formation drill in the South China Sea.