"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.

Secretary of State Marco Rubio said on Thursday that President Donald Trump's offer to “buy” Greenland is “not a joke”, adding that acquiring the semi-autonomous Danish territory was in the US “national interest”.

Rubio said he could not predict if Trump would succeed in buying Greenland from Denmark or restoring American authority over the Panama Canal while he is in office.

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.