The United States, Britain and Australia are advancing their trilateral partnership over a range of advanced military capabilities, White House press secretary Jen Psaki said Wednesday, denying a media report that the group is asking Japan to take part.

The report is "inaccurate," Psaki said, noting that the top Japanese government spokesman has also denied the claim that Tokyo was approached over possible AUKUS participation.

"Our focus has been on finalizing a trilateral program of work on a range of advanced military capabilities that align our priorities, amplify our collective strengths and accelerate the development and acquisition of leading-edge defense capabilities," Psaki said.

"It is not a 'JAUKUS' plan," she added.

The Japanese daily Sankei Shimbun reported Tuesday that each AUKUS member had informally asked Japan, a key U.S. security ally, about the possibility of it joining the partnership, which was launched in September last year with a focus on the Indo-Pacific region amid China's growing assertiveness.

The newspaper also said that if Japan were to join AUKUS, which stands for Australia, the United Kingdom and the United States, the expanded partnership may then be called "JAUKUS."

Under the first AUKUS initiative, Australia will seek to acquire nuclear-powered submarines through technical cooperation with the other partners.

The leaders of the three countries also announced earlier this month a new trilateral cooperation on the development of hypersonic weapons and electronic warfare capabilities.

They have also said they will "seek opportunities to engage allies and close partners" as their work progresses on key defense and security capabilities.