The UK, US and Australia have announced a historic security pact in the Asia-Pacific, in what's seen as an effort to counter China.

It will let Australia build nuclear-powered submarines for the first time, using technology provided by the US.

The pact, to be known as Aukus, will also cover artificial intelligence, cyber and quantum technologies.

It is the biggest defence partnership among the countries in decades, analysts say.

China's embassy in Washington reacted by accusing the countries of a "Cold War mentality and ideological prejudice".

In recent years, the Western democracies have all expressed concerns about China's growing military assertiveness.

The new partnership aimed to "promote security and prosperity" in the region, said US President Joe Biden, UK Prime Minister Boris Johnson and his Australian counterpart Scott Morrison in a joint virtual press briefing.

But in one awkward moment, Mr Biden appeared to forget Mr Morrison's name, referring to him as "that fellow down under".

The pact means Australia has torn up a A$50bn (€31bn; £27bn) deal it signed with France in 2016, to build 12 submarines.

What is Aukus?

It is probably the most significant security arrangement between the three nations since World War Two, analysts say.

The pact will focus on military capability, separating it from the Five Eyes intelligence-sharing alliance which also includes New Zealand and Canada.

While Australia's submarines is the big-ticket item, Aukus will also involve sharing of cyber capabilities, AI, quantum and other undersea technologies.

"This is an historic opportunity for the three nations, with like-minded allies and partners, to protect shared values and promote security and prosperity in the Indo-Pacific region," the joint statement read.

The leaders did not refer to China directly, but said regional security challenges had "grown significantly".