President Trump’s pick to become America’s ambassador to Iceland has apologized for joking about the small Arctic nation becoming part of the United States, a quip that caused an uproar in Iceland amid Trump’s continued push to acquire its neighbor, Greenland.

Billy Long, a former Republican member of Congress from Missouri, told the Alaska-based site Arctic Today that “there was nothing serious” about his comments. “If anyone took offense to it, then I apologize,” he added.

Though Long didn’t confirm the exact nature of what he said, Politico reported on Wednesday that he was overheard joking during a conversation on the House floor that Iceland would become the 52nd state and he would be named governor.

Long said the comment came in the context of a conversation with Louisiana Gov. Jeff Landry, whom Trump has named as a special envoy to Greenland to continue his campaign to make the massive Danish territory part of the U.S.

“They were kidding about Jeff Landry being governor of Greenland and they started joking about me,” Long said.

Government officials in Iceland apparently did not find Long’s joke funny.

Iceland’s foreign ministry told a local news outlet that it had contacted the U.S. embassy in its capital, Reykjavik, to “examine the truthfulness of the alleged comments.”

Sigmar Guðmundsson, a member of Iceland’s Parliament who sits on its Foreign Affairs Committee, told the country’s public broadcaster that Long’s comments were “not particularly funny.”

“In fact, these are really rather serious remarks. But perhaps this tells us quite a lot, unfortunately, about the disrespect that is taking root in the United States towards the sovereignty of small states,” he said. “There is no need to say much more than that this is extremely serious for a small country like Iceland.”

More than 3,500 Icelanders have signed a petition calling on the government to invoke its power to reject foreign ambassadors and refuse to allow Long to represent the U.S. in Iceland.

“These words by Billy Long … may have been spoken in a half-hearted manner, but they are insulting to Iceland and Icelanders,” the petition reads.

Trump has vowed to make Greenland part of the U.S. “one way or the other” and has repeatedly suggested he’d consider using military force to accomplish that goal, a step that, according to a new Yahoo/YouGov poll, most Americans say they oppose. Neither the president nor any high-ranking member of his administration has expressed similar interest in obtaining Iceland.

Although the two islands share many similarities, Iceland and Greenland are distinct in many ways. Most importantly, Iceland is its own nation, having declared its independence from Denmark in 1944. Greenland, on the other hand, is still officially under Danish rule — though its citizens have wide authority to govern themselves in most cases. Iceland is much smaller but it is home to seven times as many residents as Greenland, and its economy is 10 times bigger.

Before the hubbub over Long’s comments, Iceland’s most famous citizen, the singer Björk, expressed solidarity with the citizens of her country’s Arctic neighbor in a social media post and urged them to seek their own independence.

“Colonialism has repeatedly given me horror chills up my back, and the chance that my fellow greenlanders might go from one cruel coloniser to another is too brutal to even imagine,” she wrote. “Declare independence !!!!”