The source said that European allies would also step up Arctic security, but insisted that placing American bases on Greenland under US sovereignty had not been discussed.

"The 1951 agreement will get renegotiated," the source said.

The defence agreement, updated in 2004, already gives Washington freedom to ramp up its troop deployments, provided it informs the authorities in Denmark and Greenland in advance.

The US currently has one base on Greenland -- the Pituffik Space Base on the northwest of the island that constitutes a crucial link in the US missile defence system.

Trump on Wednesday announced a framework deal after talks with Rutte at the World Economic Forum in Davos, but the details of the purported agreement remained vague.

Rutte said on Thursday one "work stream" to emerge from the meeting was "that we ensure that the Chinese and the Russians will not gain access to the Greenland economy" or militarily.

Trump's threats to take Greenland have rocked the transatlantic alliance and plunged NATO into its biggest crisis in decades.

Some European nations have pushed for NATO to launch a mission in the Arctic to try to shore up security in the region after Trump used it to justify his desire for Greenland.