Public school students in Australia's Northern Territory must sing the national anthem at all assemblies and special events to help restore pride in the country, a new ruling says.

President Donald Trump and Minnesota Governor Tim Walz said they had a productive discussion on immigration enforcement, in a possible sign that Trump might consider de-escalating a surge of agents who have killed two US citizens in the state.

British lawmaker Suella Braverman, a former interior minister, has become the latest prominent Conservative to join Nigel Farage's right-wing Reform UK party, as she accused her former party of lying to voters over immigration.

US immigration agents shot and killed a US citizen in Minneapolis on Saturday, officials said, sparking fierce protests and condemnations from local leaders.

President Donald Trump says he has secured total and permanent US access to Greenland in a deal with NATO, whose head says allies will have to step up their commitment to Arctic security to ward off threats from Russia and China.