MOSCOW, July 25. /TASS/. A Mi-28 helicopter crashed in Russia’s Kaluga Region during a routine flight, the crew was killed, the Defense Ministry said.

"An Mi-28 helicopter crashed in the Kaluga Region while performing a routine flight. The helicopter went down in a deserted area. There is no destruction on the ground. The crew was killed," the ministry said.

According to the military, a technical malfunction has become the preliminary cause of the helicopter crash.

"A commission of the Russian Aerospace Forces is working at the site of the crash," the ministry added.