MOSCOW, September 14. /TASS/. More than 50 Russian air force planes and helicopters have tested the operation of the air defense alert forces of Russia’s Western Military District at the Russian-Belarusian Zapad-2021 joint exercises, the Russian Defense Ministry said in a statement on Tuesday.

"More than 50 aircraft were scrambled, including An-2 small-capacity planes, An-26 transport planes, Su-35S and MiG-31 jets as well as Mi-8 and Ka-52 helicopters. The aircraft were tasked with breaching the alert zone of the air forces unnoticed to radiolocation stations of the radio-technical troops," the statement reads.

The biannual Zapad-2021 exercises are held on September 10-16 on the training grounds of Russia and Belarus. The event involves about 200,000 servicemen, over 80 planes and helicopters and up to 760 vehicles. The scenario presupposes a reaction to an escalation of the international situation and potential aggression against the Union State. Both Russia and Belarus repeatedly stated that this exercise is defensive in nature.