The United States and Estonia will conduct observation flights over Russia and Belarus under the Treaty on Open Skies this week, Sergei Ryzhkov, head of Russia’s National Nuclear Risk Reduction Center, announced Sunday.

The American and Estonian inspectors will fly over the territory of Russia and Belarus sometime between April 6 and April 11 using the Boeing OC-135B American observation aircraft, Ryzhkov said. Russian and Belarusian specialists will also board the plane to monitor whether the foreign experts are using the equipment properly and adhering to the rules of the treaty, he added.

“Within the framework of the international Treaty on Open Skies a US mission with the participation of Estonian representatives plans to conduct an observation flight over the territory of a group of participating states, the Republic of Belarus and the Russian Federation, on the American OC-135B observation aircraft,” Sputnik quoted Ryzhkov as saying.

The OC-135B plane does not include any weapons, but is equipped with observation technology approved by the Treaty on Open Skies. The treaty allows 34 participating countries to carry out observation flights over each other's territories to gather information through aerial imaging on military forces and activities that are of concern to them.

Signed in March 1992 in Helsinki, the treaty came into force on Jan. 1, 2002. Russia ratified the treaty on May 26, 2001. In December, Russia guided a similar flight over the U.S., covering a maximum range of 2,640 miles. The flight was launched from Travis air force base in California.