"This is in our national interest and it needs to be solved," Rubio said. Greenland's prime minister has repeatedly said the island is not for sale.

The secretary of State said purchasing the Danish territory is important to the country’s national interests in the Arctic.

Trump’s bid for the Arctic territory was laughed off as a joke. Now, it’s gaining traction and provoking jitters in Europe.

President Trump told Denmark’s leader he wanted to take over Greenland, European officials say. Denmark has asked its E.U. allies not to inflame the situation until Mr. Trump’s intentions are clearer.