Russian air defense on Thursday shot down "an unidentified object" near the key military base of Engels, located 500 kilometers from the Ukrainian border and already hit on Monday by a deadly drone attack attributed to Ukraine.

“An air defense system was activated in the territory of the Engels district. An unidentified object was destroyed [...] No threats to the safety of the inhabitants”, indicated on Telegram the regional governor, Roman Boussargine.

“Again, messages about the need for an evacuation (of the town) of Engels are being broadcast. I call for calm. No evacuation of the city is necessary,” he added.

The Russian military airfield of Engels, located in this area, was hit on Monday by a drone attack which caused the death of three soldiers, according to Moscow. They were killed by debris from a Ukrainian drone after it was destroyed by air defense.

On December 5, Moscow also accused Ukraine of launching drone attacks against the Engels base and another in the Ryazan region.

This is therefore the third incident, in a month, affecting the surroundings of this Russian air base, known to shelter strategic bombers, devices designed for attacks against targets of high importance.

This new incident comes as Ukraine denounced Thursday new "massive" Russian strikes on its energy infrastructure.