China is gravely concerned about the expansion of the Australia-United Kingdom-United States trilateral security partnership, saying it would severely undermine peace and stability in the Asia-Pacific region, a defense spokesman said on Thursday.

Wu Qian, the spokesman for the Ministry of National Defense, made the remarks in response to reports that Japan has officially announced its intention to join AUKUS and that Canada is considering starting negotiations on joining the security alliance.

"We are open to normal military cooperation between any countries, but we firmly oppose relevant countries cobbling together exclusive groupings, building bilateral or multilateral military alliances targeting China, creating division and stoking block confrontations," he said.

The Asia-Pacific region is a big stage for peace and development, not a wrestling ground for geopolitical competition, said Wu, stressing that "China is a cooperation partner for all countries, not a challenge to anyone."

In disregard of the concerns of regional countries and the international community, the US, UK and Australia have kept sending signals of AUKUS expansion, which has severely undermined peace and stability in the Asia-Pacific region, he said, adding that many regional countries are deeply concerned about it.

The spokesman noted that, for historical and realistic reasons, Japan's military and security moves have been closely watched by its Asian neighbors and the international community.

"Japan needs to draw lessons from history and speak and act prudently on military and security issues," he said.

"Other countries should also earnestly fulfill their international obligations and avoid doing things that may undermine regional and world peace and stability," Wu added.