Von der Leyen's comments come as US officials will host the Danish and Greenlandic foreign ministers at the White House for crunch talks later on Wednesday.
European Commission President Ursula von der Leyen expressed support for Greenland on Wednesday, saying the Arctic island which US President Donald Trump has vowed to seize "belongs to its people".
"For me it's important that the Greenlanders know and they know this by the deeds, not only by the words, that we respect the wishes of the Greenlanders and their interests and that they can count on us," she said at a press conference in Brussels.
Her comments come as US Vice President JD Vance and Secretary of State Marco Rubio will host the Danish and Greenlandic foreign ministers at the White House later on Wednesday.
Denmark's Foreign Minister Lars Lokke Rasmussen told reporters that he and his Greenlandic counterpart, Vivian Motzfeldt, had requested a meeting with US President Donald Trump after he escalated his threats to annex the self-governing Danish territory.
"Our reason for seeking the meeting we have now been given was to move this whole discussion ... into a meeting room where we can look each other in the eye and talk about these things," Rasmussen said in Copenhagen on Tuesday.
Tensions have soared between the US, Denmark and Greenland this month as Trump and his administration continue to push the issue.
The US president has repeatedly refused to rule out using military force to take the island.
Trump said on Wednesday that US control of Greenland was "vital" for his planned Golden Dome air and missile defence system.
"The United States needs Greenland for the purpose of National Security. It is vital for the Golden Dome that we are building," Trump wrote in a post on social media.
"NATO becomes far more formidable and effective with Greenland in the hands of the United States. Anything less than that is unacceptable."
Denmark's defence minister said on Wednesday that it would "strengthen" its military presence in the Arctic territory and was in dialogue with allies in NATO.
"We will continue to strengthen our military presence in Greenland, but we will also have an even greater focus within NATO on more exercises and an increased NATO presence in the Arctic," Troels Lund Poulsen said.
Lund Poulsen added that Denmark "has an ongoing dialogue with its allies about new and increased activities in 2026."
Trump mocked Greenland's security forces on Monday, saying: "You know what their defence is, two dog sleds," while claiming that Russia and China have "destroyers and submarines all over the place."
Denmark's Prime Minister Mette Frederiksen has said her country faces a "decisive moment" in its diplomatic battle with the US over Greenland, warning that if Washington uses force to seize the island it will signal the end of NATO.