President Donald Trump has reportedly asked his advisers to research the United States purchasing Greenland from Denmark.

Both The Wall Street Journal and The Associated Press reported on the plan, with the Journal saying the discussions had “varying degrees of seriousness” and an AP source calling it “not serious.”

Former Denmark Prime Minister Lars Lokke Rasmussen wondered if the idea was an out-of-season April Fool’s Day joke. MSNBC’s Rachel Maddow cracked that Trump would turn Greenland into a golf course once the glaciers melted due to climate change. And the reports caused #Greenland to trend on Twitter, where the plan received given a frosty reception from Trump’s critics: