The commander of a strike group led by the British aircraft carrier Queen Elizabeth on Tuesday described their visit to Japan as the "cornerstone" of their dispatch to the Indo-Pacific region.

The remark came as the Queen Elizabeth made its first port call in Japan on Saturday in a bid to showcase the robust ties between the two nations as Tokyo and London deepen their defense cooperation in response to China's military buildup and assertive territorial claims in the East and South China seas.

The deployment to Japan is "a demonstration of the U.K.'s commitment to investing in our partnership with Japan," Commodore Steve Moorhouse said in a virtual press conference.

Screenshot shows Commodore Steve Moorhouse, commander of the strike group centered on Britain's aircraft carrier the Queen Elizabeth, speaking at a virtual press conference on Sept. 7, 2021. (Kyodo)

Britain has been stepping up its role in the Indo-Pacific region, having said in its March defense and foreign policy review that it will be "deeply engaged" in the region.

The tilt is partly driven by Beijing's attempts to undermine the rule of law, democracy and human rights such as in Hong Kong, a former British colony.

As the strike group sailed through the South China Sea, Moorhouse said their vessels were "escorted, shadowed by Chinese units," referring to Chinese naval ships. But he added that China's naval activities were "safe and professional."

The Queen Elizabeth, commissioned in 2017, is Britain's largest aircraft carrier with state-of-the-art weaponry, capable of carrying up to 40 aircraft, including British and U.S. F-35B advanced fighter jets, according to the Royal Navy.

Since August, the strike group, joined by a Dutch frigate and a U.S. destroyer, has been conducting a series of joint exercises with the Japanese Self-Defense Forces, in a veiled counter to China's rising assertiveness in the region.

Screenshot shows Julia Longbottom, British ambassador to Japan, speaking at a virtual press conference on Sept. 7, 2021. (Kyodo)

Julia Longbottom, the British ambassador to Japan, who joined the press conference, expressed hope that their countries will make "reciprocal arrangements," referring to a bilateral pact aimed at facilitating joint exercises between their troops.

"This will allow us to pursue increasingly complex and meaningful U.K.-Japan cooperation to contribute to peace and stability in the Indo-Pacific and beyond," she said.

The Queen Elizabeth, which left Britain in May and arrived at the weekend at the U.S. Navy base in Yokusuka, southwest of Tokyo, is scheduled to depart later this week.

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