US Vice-President JD Vance says Greenland is "critical" for the defence of the US and the world against possible Russian or Chinese missile attacks - and that Europe and Denmark have "not done a good job" in securing the area.
Vance told Fox News that they had not only under-invested in Greenland's defences, but also failed to engage with President Donald Trump's argument over the issue.
US officials are "actively" discussing a potential offer to buy Greenland - a semi-autonomous Danish territory - the White House said on Wednesday, a day after suggesting military action to annex it to the US was also an option.
Denmark, a fellow Nato member, has warned this would spell the end of the alliance.
Both Greenland and Denmark have repeatedly stressed the island is not for sale.
