He made these remarks just after landing in Ankara, Turkey, for a NATO gathering.
Trump told reporters that Greenland "should be controlled by the United States." During a one-on-one discussion with Turkish President Recep Tayyip Erdogan, Trump complained that Europe's unwillingness to support his Greenland plan "hurt my relationship with NATO."
"Because Greenland doesn't help Denmark. Denmark doesn't spend money to really help Greenland, but it's an important part for the United States," Trump said.
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He pointed to Chinese and Russian ships near the island. "And it's surrounded by China ships and Russian ships, and that's not going to happen, the ships, is, it's not going to happen," Trump stated, reiterating allegations of foreign military dangers that specialists on Greenland have refuted.
Greenland "should be controlled by the United States, not by Denmark," Trump went on. "And when they wouldn't go along with it, and with all the money we spend to help them with Russia - we don't have to spend any money."
"And they better be careful," Trump continued, addressing Europe in general terms, "with immigration and energy. If they're not careful with those two things, you're not going to have a Europe anymore." After that, he closed the part of the session accessible to journalists.
The president's campaign to acquire the island had turned into a significant cross-Atlantic controversy earlier this year, fueled by his repeated claims that the territory ought to be governed by the United States. Greenlandic legislators have repeatedly stated that the island is not available for purchase.
Trump, who had previously declined to exclude the possibility of using military action to seize Greenland, unexpectedly declared in late January that a "framework of a future deal" regarding the territory had been crafted by him and NATO Secretary General Mark Rutte.
When queried on Tuesday regarding Trump's most recent Greenland remarks, Finnish President Alexander Stubb informed CNBC's Steve Sedgwick: "Be more Arctic, be more cool. If it is about Arctic security, we have seven countries that are Arctic nations in the alliance."
He added: "Finland has trained 1 million soldiers in Arctic conditions; we basically live in Arctic conditions. Let's keep that in mind. Let's, you know, continue the process that the Danes, the Americans and the Greenlanders have."
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