The head of Russia’s Nuclear Risk Reduction Center said that Russian inspectors will conduct an aerial surveillance flight over Denmark in a Tu-154M-LK-1 surveillance aircraft within the scope of the Treaty on Open Skies.

“The surveillance flight over Denmark will be carried out between September 12-17, 2016, taking off from the open skies Aalborg Airport and using the Sondre Stremfjord airfield in Greenland to refuel. The maximum flight range will be 5,600 kilometers [3,500 miles],” Sergei Ryzhkov said.

Danish experts will be on board the plane to oversee the observance of treaty clauses, he added, noting that route details have been agreed on.

The Treaty on Open Skies entered into force from 2002, providing for unarmed aerial surveillance flights between member states. With 34 states ratifying the agreement, 27 states are Organization for Security and Co-operation in Europe (OSCE) members. Russia ratified the agreement in 2001.