"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.

US President Donald Trump is serious about seeking to buy Greenland, Secretary of State Marco Rubio said on Thursday, after Denmark was rattled by his threats to take over the autonomous Danish territory.

President Donald Trump's interest in buying Greenland is "not a joke," Secretary of State Marco Rubio said in an interview on Thursday, adding that acquiring Greenland was in U.S. national interest and needs to be solved.

An opinion poll indicated on Tuesday that 85% of Greenlanders do not wish their Arctic island - a semi-autonomous Danish territory - to become a part of the United States, Danish daily Berlingske reported.

As much as President Donald Trump wants Greenland to become part of the United States, Greenlanders do not want to join the U.S. So says a poll conducted for Greenlandic newspaper Sermitsiaq and Denmark’s Berlingske,

As President Trump pushes for Greenland to join the U.S., a new poll finds 85% of the semi-autonomous Danish territory's residents oppose the move. Why it matters: Trump has stepped up his push push for Greenland since he won November's election despite the terrotory's leader and Denmark's prime minister saying it's not for sale and told reporters Saturday he thinks the U.