China’s first aircraft carrier Liaoning will conduct open-sea training exercises in the Western Pacific, the country’s defense ministry said Sunday. A navy formation including the Liaoning headed for the training Saturday as part of an annual training program, according to Chinese state media.

The Liaoning was commissioned by the Chinese navy in 2012 and last month Beijing said that the aircraft was geared up to engage in combat. The carrier was reportedly bought as an incomplete hull from Ukraine over a decade ago.

On Friday, the Chinese military announced that the carrier performed a series of fighter launch, recovery and air combat drills slightly farther afield in the Yellow Sea. The following day, it reportedly conducted training in the East China Sea.

“Liaoning will conduct further drills in other parts of China’s maritime area which includes the Bohai Sea, the Yellow Sea, the East China Sea and the South China Sea,” Global Times reported.

A Japanese defense destroyer spotted the Chinese aircraft carrier in the central part of the East China Sea for the first time, according to the Japanese defense ministry. The carrier did not enter Japanese waters, the ministry added.

The latest development comes amid tensions between China and the U.S. after Beijing seized the latter’s underwater drone in the South China Sea. China said that it would return the drone, but it remains unclear when that would happen.

Following the incident, President-elect Donald Trump launched an attack on China on Twitter. He has already upset Beijing with his comments on the “one China” policy and a phone call with Taiwanese President Tsai Ing-wen following his election win last month.