A US military raid on Caracas on Saturday that captured Venezuelan President Nicolas Maduro has rekindled worries in Denmark and among its European allies that Greenland, an autonomous Danish territory, might face a similar scenario.
The White House said on Tuesday that Trump was discussing options for acquiring the strategic Arctic island despite European objections.
Asked on Wednesday about Denmark's offer to discuss the situation in Greenland, Rubio said: "I'll be meeting with them next week. We'll have those conversations with them then."
Asked if Trump planned for the US to buy Greenland, Rubio said that this had always been the president's intent.
"If the president identifies a threat to the national security of the United States, every president retains the option to address it through military means. As a diplomat, which is what I am now, and what we work on, we always prefer to settle it in different ways - that included in Venezuela," Rubio told reporters.
Trump, who first voiced the idea of the US gaining control of Greenland in 2019 during his first presidency, argues the island is key for US military strategy and claims Denmark has not done enough to protect it.
Rubio told a select group of lawmakers that it was the administration's intention to eventually purchase Greenland.
The remarks, first reported by the Wall Street Journal, were made in a classified briefing on Monday evening on Capitol Hill, according to a person with knowledge of his comments who was granted anonymity because it was a private discussion.
Trump said on Wednesday that the United States would "always" stand by the NATO military alliance.
"We will always be there for NATO, even if they won't be there for us," Trump wrote on his social media platform Truth Social.
Trump added that Russia and China would not "fear" NATO if the United States were not part of the alliance.
"EVERYONE IS LUCKY THAT I REBUILT OUR MILITARY IN MY FIRST TERM, AND CONTINUE TO DO SO," he wrote.
White House Press Secretary Karoline Leavitt said on Tuesday that Trump was considering a range of ideas regarding Greenland and that "utilising the US military is always an option".
Danish Prime Minister Mette Frederiksen warned that a US attack on another NATO member would shatter the alliance.
"If the United States decides to militarily attack another NATO country, then everything would stop - that includes NATO and therefore post-WWII security," she said this week.
NATO currently has 32 member states.
At the core of the alliance is Article 5 of the NATO treaty, which commits members to collective defence, stipulating that an armed attack against one member is considered an attack against all.
Greenland is about four-fifths covered by ice and has a population of fewer than 57,000.
Trump has framed its acquisition as part of a growing strategic contest in the Arctic involving powers such as China and Russia as well as a way to secure access to critical minerals.
with AP and DPA
