According to the Danish broadcaster, the NSA and Danish military service FE signed an agreement in 2008, which stated that the Americans would help Denmark tap internet cables in the European country. In return, the NSA gained access to internet cables to Eastern Europe. Together they processed the data in a data center near Copenhagen Airport, which was built for that purpose.
But the United States also used that internet access to spy on Denmark itself, and surrounding countries including the Netherlands, Germany and Sweden, the whistleblower, a former employee of the FE, said to DR.