Russian military inspectors started a surveillance flight over Greece on Monday under the international Open Skies Treaty, the Defense Ministry said.

The inspections, conducted in an An-30B aircraft, will last till Friday and cover a total distance of 1,010 km, the ministry said on its website.

During the flight, Russian and Greek inspectors will operate surveillance equipment onboard the aircraft as envisaged by the Open Skies Treaty.

"This will be Russia's first observation flight in 2013 over the territories of the treaty's participants," the ministry said.

The Open Skies Treaty came into force on Jan. 1, 2002. It establishes a regime of unarmed aerial observation flights over the territories of its 34 member states to promote openness and the transparency of military forces and activities.