According to Russia’s National Nuclear Risk Reduction Center director Sergey Ryzhkov, the United States conducted an observation flight in Russia using U.S. aircraft OC-135B from April 10 to April 14, 2017. The Russian side cleared the U.S. observation plane, which also carried on board military personnel from the Czech Republic, pursuant to the Open Skies Treaty. Mr. Ryzhkov indicated that the plane did not carry weapons.

Russian officials were also on board the aircraft to ascertain that the surveying equipment was properly utilized.

The Open Skies Treaty was entered into in 1992 as a measure designed to boost confidence between Russia and the U.S. following the dissolution of the U.S.S.R. The treaty became effective in 2002. The treaty’s membership is up to 34 countries, which include most NATO block countries.