"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 says President Donald Trump’s desire to acquire Greenland and retake control of the Panama Canal is driven by legitimate national security interests stemming from growing concerns about Chinese activity in the Arctic and in Latin America.

Rubio defended Trump's proposed territorial expansions as a 'national interest,' while Denmark and Greenland firmly rejected offers amid concerns over potential military action.

Denmark said on Monday it would spend 14.6 billion Danish kroner ($2.05 billion) boosting its military capabilities in the Arctic – a decision that comes amid continuing furor following US President Donald Trump’s renewed interest in controlling Greenland,

It was a contentious, aggressive telephone call, five days before the inauguration of President Donald Trump on Jan. 20.