Denmark called for the US ambassador over a report that Washington was increasing its espionage activities against politicians in Greenland and Copenhagen.
Danish Foreign Minister Lars Løkke Rasmussen said on Wednesday that he had read the news in the Wall Street Journal with "deep concern", contacted the US ambassador to convey "friends" and concerns about Copenhagen's espionage activities.
This incident was the latest tension between the two NATO allies since US President Donald Trump reiterated earlier this year that he wanted to take control of Greenland, the semi-autonomous region of the Danish kingdom, under Washington's control.
Greenland MP Pipaluk Lynge said the leaders of the Arctic island and the leaders of Denmark should consider closing the US consulate in the region's capital Nuuk.
According to the WSJ, a secret message was sent to US intelligence agencies last week, asking to identify people in Greenland and Denmark who support Trump's goal of taking control over the geopolitically important island.
The heads of the intelligence agencies were instructed to learn more about Greenland's independence movement and the attitude of American companies towards mining activities, the news said.
National intelligence director Tulsi Gabbard did not deny the news, but criticized the newspaper for "tooling and leaking confidential information for politics".
The Danish Security and Intelligence Service announced late Wednesday that “the threat of espionage and foreign states of penetration is increasing” due to U.S. interest in Denmark and Greenland.
According to the Financial Times, tensions over Greenland escalated between Copenhagen and Washington after Trump insisted on his phone call with Danish Prime Minister Mette Frederiksen in January that he would take control of the island with a population of 57,000.
Denmark intensified its criticism of the US after Vice President JD Vance made an uninvited visit to a US military base in Greenland in March, harshly criticizing Copenhagen for neglecting this region.
Danish officials were also “horrified” that Vance said that the Scandinavian country was not a good ally despite fighting alongside the US in Afghanistan and losing as many troops as the United States compared to its population.
Lynge, the head of the security committee of the Greenland parliament, said the island's politicians should consider taking serious steps against the United States.
He told the Danish television channel DR, "You have to talk about the Trump administration as it is. This is a wolf disguised as a lamb. Is NATO the same as before? I don't think it's like that when you spy on each other," he said.