A Russian Mi-28 attack helicopter crashed in Kaluga Oblast in western Russia, Governor Vladislav Shapsha reported on July 25.
Preliminary evidence indicates that the cause of the crash was a technical malfunction. The helicopter's crew was killed, the Russian Defense Ministry said.
The helicopter reportedly fell into a deserted area near the village of Klenki, lying over 100 kilometers (over 60 miles) east of the Ukrainian border. No damage on the ground was reported.
"A task force and rescuers are working on the crash site," Shapsha said on his Telegram channel.
The Mi-28, also known under the NATO reporting name "Havoc," is a two-seat anti-armor gunship helicopter developed in the Soviet Union during the 1980s.
Russia has deployed the aircraft in Ukraine during its full-scale invasion. According to the Ukrainian military, Moscow has lost 326 helicopters in combat throughout the all-out war.
The incident follows another helicopter crash last week.
A Robinson helicopter disappeared in the Yakutia region in eastern Siberia on July 19. Its wreckage was found soon after, with the pilot and three passengers killed.
According to unconfirmed reports by Russian media, the three killed passengers were officers of Russia's Federal Security Service (FSB).
There have been several cases of Russian helicopters and planes crashing during the full-scale war, sometimes resulting in fatalities. Russia's aviation industry took a heavy hit as a result of Western sanctions, often lacking the necessary components to maintain the aircraft.