Russia began observational flights over the United States on Sunday under the international Open Skies Treaty, officials said.
The monitoring missions are being carried out by a Tupolev Tu-154M/LK-1 aircraft through Aug. 12, RIA Novosti reported.
"The missions will be carried out from the Travis Air Force Base [in California] and Wright-Patterson Air Force Base [in Ohio]," said Sergei Ryzhkov, head of Russia's National Nuclear Risk Reduction Center. "These will be Russia's 23rd and 24th monitoring flights in 2013 over the territories of the Open Skies Treaty member states."
Russian military inspectors, along with U.S. specialists, will monitor surveillance equipment aboard the aircraft.
The Open Skies Treaty allows participants to conduct unarmed aerial observation flights over the territories of its 34 member states to promote openness of military forces and activities.
The treaty went into effect Jan. 1, 2002.