Britain is discussing with NATO allies how to enhance Arctic security against Russia and China. Transport Secretary Heidi Alexander said Sunday that these talks are routine and not a response to U.S.

US President Donald Trump has raised doubts about America’s continued commitment to NATO, saying he is not sure the alliance would come to the United States’ defence if it were attacked. Trump’s remarks have reignited debate over Washington’s role in the transatlantic military bloc.

The response comes amid concerns over Russia's continued military build-up in the region and its close ties to China.

Britain said on Sunday discussions with other NATO members on deterring Russian activity in the Arctic were "business as usual", after media reports the UK was in talks with its European allies about deploying a military force to Greenland.

Trump’s threat to annex an autonomous part of Denmark has plunged NATO into an unprecedented situation: An alliance based on collective defense now faces the prospect that one member might attack another.

President Donald Trump pledges U.S. will "always be there for NATO" while questioning alliance's commitment amid tensions over Greenland push.

Top Trump aide Stephen Miller says it's the "formal position" of the White House that Denmark's territory of Greenland "should be part of the U.S."

As U.S. President Donald Trump insists his country needs Greenland for security purposes, Canada's former top soldier is warning that a U.S. takeover of the area could spell the end of the North Atlantic Treaty Organization.