His comments come as Danish and Greenlandic envoys are expected in Washington this week for talks.
In a post on Facebook, Denmark’s Frederiksen said Sunday that “disagreements and conflicts between the United States and Europe only benefit our adversaries. They weaken us and strengthen them.”
“Denmark is a loyal and strong ally. We are in the midst of a significant rearmament, and we are ready to defend our values — wherever it is necessary — also in the Arctic,” Frederiksen added. “We believe in international law and in peoples’ right to self-determination.”
Frederiksen said last week that an American attack on a NATO state would mean the end of the alliance, a message echoed Monday by European Union Defense Commissioner Andrius Kubilius.
Kubilius also said that the E.U. Treaty obliged member states to come to Copenhagen’s assistance if faced with military aggression, but that “it will depend very much on Denmark.”
Trump told reporters on Air Force One that although he “liked” the alliance, NATO needed the U.S. more than the other way around.

Trump also reiterated his previous disparaging comment about Greenland’s defense, saying it consists of “two dog sleds.”
“In the meantime, you have Russian destroyers and submarines and China destroyers and submarines all over the place,” he added.
Experts have questioned the presence of these ships, and Beijing pushed back Monday at Trump’s assertions that China had designs over Greenland.
“The Arctic involves the collective interests of the international community,” Chinese Foreign Ministry spokesperson Mao Ning said in a daily briefing, adding that China’s activities in the region were “promoting peace, stability, and sustainable development” while complying with international law.
“The United States should not use other countries as an excuse to pursue its own private interests,” she added.