The official said two facilities at the Signal plant in the city of Stavropol, about 540km from the Ukrainian border, were damaged in the attacks. He shared several short videos showing an explosion and a large column of dark smoke rising into the sky.

He said the plant was one of Russia’s leading producers of electronic warfare equipment, including radar, radio navigation equipment, and remote control radio equipment.

“This night, long-range SBU drones struck the production facilities of the Stavropol radio plant ‘Signal’,” said the SBU official.

“Each such attack stops production processes and reduces the enemy’s military potential. This work will continue.”

Reuters was unable to verify the details of the attack. Russia’s defence ministry did not immediately respond to a request for comment.

Since Russia’s invasion of Ukraine in February 2022, both sides have launched multiple drone attacks on each other.

Ukraine, which is fighting a much larger Russian army, has developed a drone industry from scratch and is now focusing on increasing its capacity to produce more long-range drones.