US President Donald Trump’s nominee for ambassador to Iceland, former Representative Billy Long, apologized on Thursday for joking that the island nation could become the 52nd US state with himself as governor.

The remark comes as Trump’s statements regarding Greenland have escalated in recent weeks, with the US president increasingly insistent on acquiring the territory from Denmark and hinting at potentially taking the North Atlantic island by force.

Long told Arctic Today that his comments, made on Tuesday, were intended as humor in response to a separate joke about Jeff Landry, Trump’s special envoy to Greenland.

“There was nothing serious about that,” Long, a former Missouri Republican congressman who briefly served as commissioner of the Internal Revenue Service under Trump last year, told the outlet. “I was with some people, who I hadn’t met for three years, and they were kidding about Jeff Landry being governor of Greenland and they started joking about me and if anyone took offense to it, then I apologize.”

The joke has sparked criticism in NATO member Iceland. On Thursday, the Foreign Ministry told local media it had contacted the US Embassy in Reykjavík seeking clarification. A petition calling on Icelandic Foreign Minister Thorgerdur Katrin Gunnarsdottir to reject Long as ambassador has also been launched, drawing more than 2,000 signatures as of publication.

The scandal comes as Trump has issued repeated threats to seize Greenland, an autonomous Danish territory. On Wednesday, the US president offered a new rationale, saying control of the world’s largest island – which has a population of around 57,000 people but is 2.16 million square kilometres (836,330 square miles) in size – is necessary for his Golden Dome missile defense shield plan.

Trump claimed NATO would become “far more formidable and effective with Greenland in the hands of the US,” adding that without America, the bloc “would not be an effective force or deterrent.”

Greenland, under Denmark’s authority, and several Western European countries have pushed back against US annexation threats, while Copenhagen has bolstered its military presence on the island. Germany, France, Sweden, Norway, Finland, and the Netherlands have said they are sending additional military personnel to prepare for larger drills later this year.

Trump also repeated his allegation that if the US does not seize Greenland, Russia and China will. The claim has been disputed by both Moscow and Beijing, as well as challenged by officials in Greenland itself.