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. 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.Australia is going to build nuclear submarines as part of a new broader defence technology pact with the US and the UK.