The headquarters responsible for defending the airspace over Canada and the United States is sending military aircraft to Greenland amid a tense international standoff over the Danish-administered island’s future.

Colorado-based North American Aerospace Defense Command (NORAD), which is jointly operated by the US and Royal Canadian Air Forces, said on 19 January that aircraft from both countries are deploying to the USA’s Pituffk Space Base in northern Greenland.

However, NORAD sought to downplay the significance of the move, describing it as part of “long-planned NORAD activities”.

“This activity has been coordinated with the Kingdom of Denmark, and all supporting forces operate with the requisite diplomatic clearances,” NORAD says.

The US-Canadian headquarters says the government of Greenland was also informed of planned military activities.

NORAD did not specify how many aircraft and of what type are involved. Canada’s Department of National Defence directed all inquries on the matter to NORAD.

It is unlikely that Canadian aircraft would be involved in any operation in Greenland going beyond routine activities. Canada’s prime minister Mark Carney has come out forcefully against any notion of the United States taking control of the island.

“We stand firmly with Greenland and Denmark and fully support their unique right to determine Greenland’s future,” Carney said at the World Economic Forum in Davos, Switzerland on 20 January.

“Our commitment to Article 5 is unwavering,” Carney added, referencing the mutual defence clause of the North Atlantic Treaty that compels signatories to defend one another in the event of an attack on sovereign territory.

Denmark, the United States and Canada are members of the NATO alliance.

Washington maintains a permanent military presence at Pituffik, which is primarily a radar hub for monitoring North America’s airspace and defending against intercontinental ballistic missiles – key missions for NORAD.

However, the deployment comes amid an international crisis driven by comments from US President Donald Trump suggesting he will seek to take control of Greenland if Denmark will not sell the autonomous territory to Washington.

Copenhagen has responded by launching open-ended military exercises in Greenland, including the deployment of Lockheed Martin F-35 stealth fighters, operational planners and a newly created Arctic special forces unit.

A number of European NATO members have also committed to send troops, including France, Germany, the Netherlands, Norway, Sweden and the UK.

Story updated 22 January with a response from Canada’s Department of National Defence