US 821st Security Forces Squadron at Thule Air Base (Picture: US Department of Defense).
US President Donald Trump has called the Prime Minister of Denmark "nasty" for the way she responded to his interest in buying Greenland.
The US President previously stated his "strategic" interest in purchasing Greenland, the largest island on Earth, in what he likened to a "large real estate deal".
Mr Trump's comments prompted negative responses from Danish territory officials, who reiterated that the semi-autonomous island is not for sale.
The Danish leader Mette Frederiksen described the idea as "absurd".
"Greenland is not Danish. Greenland is Greenlandic", she said on Sunday.
"I persistently hope that this is not something that is seriously meant."
On Wednesday, the US President cancelled a scheduled visit to Denmark, a decision which Ms Frederiksen said she was "disappointed and surprised" by.
What 'strategic' appeal might Greenland have to Trump and the United States?
Greenland is an autonomous country of the Kingdom of Denmark, self-governing since 2009.
Matters of foreign policy and security are handled by Denmark, one of several NATO members that Trump has criticised for underspending on defence, accusing them of relying on the US.
Here are some of the potential incentives that sparked the interest of the US, and a look at whether they are alone in their pursuit of the ice-covered island...
Current military foothold
The north-western coast of Greenland is currently home to Thule Air Base, the northern-most instalment belonging to the United States.
At the base, Air Force officers from 12th Space Warning Squadron use large-scale radars to detect missiles and conduct space surveillance.
Its location in the Arctic Circle is perfect for tracking intercontinental missiles and satellites in low-Earth orbit.
The ice that covers and surrounds Greenland is rapidly thawing, largely due to global warming, and speculation that large oil and gas reserves lie beneath has caused tension among leading world powers.
If conflict were to arise, these US assets would prove vital and Trump may want to join other superpowers in expanding military force in the region.
It appears that the United States is not the only nation with an interest in Greenland.
Relations between Russia and America have continued to deteriorate in recent years, the US recently withdrawing from the Intermediate-Range Nuclear Forces Treaty.
The collapse of the Cold War treaty, which banned missiles ranging from 310 to 3,400 miles, has fuelled international concern over a new arms race.
In the polar region, retreating ice has allowed a greater presence of ships in the Atlantic Ocean.
President Vladimir Putin has shown explicit interest in increasing Russian presence in the waters.
Russia's growing fleet of icebreaker vessels has made way for growing military ambitions in the Arctic.
During an Arctic forum earlier this year, Putin told leaders of Iceland, Finland, Norway and Sweden that the amount of cargo carried across the shipping lane will increase form 20 to 80 million metric tonnes by 2025.
Putin has already started to modernize several Soviet-era bases across the region, NATO keeping a watchful eye over Russia's presence - in case patrol vessels begin to appear.
The US doubled its troop count last year, the UK sending 800 Royal Marine Commandos as then-Defence Secretary Gavin Williamson observed Russian submarine activity levels not seen "since the Cold War".
Another global power attempting to gain a military foothold in the Arctic Circle, in doing so treading on the toes of the US, is China.
The latest trade-war between China and the US has led to Donald Trump stamping a 10% tariff on $300 billion-worth of Chinese imports into the States, with tensions continuing to rise after a brief truce in late-June.
Recent years have seen multiple failed bids for an increased presence in Greenland, with Denmark regularly citing loyalty to their American partners following a military rights agreement in 1951.
In 2016, Hong Kong-based General Nice Group launched a bid for a former US military base in Greenland, before Copenhagen vetoed the deal.
More recently, China's position as favourites to win the contract for a new airport in Greenland led to US concern that the facility could be used to host military aircraft in the instance of potential future conflict.
Chinese engineers soon ran into trouble securing visas to begin work on the island, and plans were withdrawn in June this year.
As mentioned, it is no secret that many nations are taking an interest in what lies beneath the ice surrounding Greenland.
There are huge oil and gas reserves in the Arctic Circle, with some people speculating it could lead to hostility from countries such as Russia.
Captain Craig Feeney, Polar Navigation Expert from City of Glasgow College, explained a potential incentive for increased Russian presence:
"If we look at the top of Greenland, it’s quite possible that there could be vast sub-sea resources."
Greenland is regarded as a hotspot for rare-earth metals and other valuable minerals, but the United States may feel a building pressure to challenge for the landscape in the Arctic, says Caroline Kennedy-Pipe, Professor of International security at Loughborough University: “No-one owns the central Arctic.
"Some more excitable commentators have talked about a gold-rush, an oil-rush in the Arctic."
"We’re expecting to see great power rivalries played out in the Arctic, particularly with the resurgent Russian and a very interested China."
Greenland has refused to acknowledge the possibility of a US purchase.
Instead, their Ministry of Foreign Affairs declared on social media that they are "open for business".