A US government plane was parked at Copenhagen Airport in June 2013 waiting to fly former National Security Agency contractor Edward Snowden to the States, according to Denmark's justice minister.
Soeren Pind said in a letter to parliament that the plane's presence "allegedly was to have been to be able to transport Edward Snowden to the United States in case he was extradited from Russia or another country".
The NSA whistleblower, who was granted asylum in Russia, leaked millions of documents about US government surveillance in 2013.
In the letter, Mr Pind regretted being unclear about the plane's presence in close US ally Denmark when quizzed by policymakers on Wednesday.
No other details were available as the case is deemed confidential.