"Danish Prime Minister Mette Frederiksen on Monday said that a US takeover of Greenland would mean the end of the NATO military alliance. On Tuesday, Frederiksen released a joint statement with the leaders of Germany, France, Italy, Poland, Spain and the UK reiterating that European allies were stepping up "to keep the Arctic safe and to deter adversaries." It comes after US President Donald Trump renewed his calls for the large Arctic island, which is an autonomous territory of Denmark, to come under Washington's control. Frederiksen said that "everything would stop" when it comes to cooperation with Washington in the event of a US attack on another NATO member. "If the United States decides to attack another NATO country, then everything would stop — that includes NATO and therefore post-World War II security," Frederiksen said. Meanwhile, Greenland's prime minister, Jens-Frederik Nielsen, called for the territory to restore "good cooperation" with the United States and urged Greenlanders not to "panic." "The situation is not such that the United States can conquer Greenland. That is not the case. Therefore, we must not panic. We must restore the good cooperation we once had," Nielsen said while speaking in Greenland's capital, Nuuk. In a social media post on Monday, he called for Trump to give up "fantasies" of annexing Greenland. "That's enough now. No more pressure. No more insinuations. No more fantasies of annexation." "We are open to dialogue," he said. "But this must happen through the proper channels and with respect for international law.""