MOSCOW - A Russian Mi-28 helicopter crashed during a routine flight in the Kaluga region, killing its crew onboard, the Russian Ministry of Defense said in a statement on Thursday.

ALSO READ: At least 18 dead in Nepal plane crash, officials say

The crash occurred in an uninhabited area, causing no damage on the ground, the ministry said, adding that the preliminary cause of the crash appears to be a technical malfunction.

READ MORE: Media: Japan MSDF helicopter wreckage found on seafloor

The Mi-28 helicopter is a Russian-made, twin-seat attack helicopter.