A Ukrainian drone attack targeting an armoury has caused a giant fireball, leading to a partial evacuation in western Russia.

The attack, reported early on Wednesday, targeted a large arsenal close to the town of Toropets, some 400km (250 miles) northwest of Moscow in the Tver region. It illustrates Ukraine’s continued effort to show it can strike at targets deep inside Russia.

The drone attack caused an “extremely powerful detonation” and destroyed a large warehouse of the Main Missile and Artillery Directorate of the Russian Ministry of Defence and sparked a fire 6km (3.7 miles) wide, an unnamed source from the Ukrainian security services said.

“The warehouse contained missiles intended for Iskander tactical missile systems, Tochka-U tactical missile systems, guided aerial bombs and artillery ammunition,” the source told news wires.

‘Contain the fire’

Without mentioning the attack on Tver, Russia’s Defence Ministry said air defence units had destroyed 54 Ukrainian-launched drones targeting five western Russian regions overnight, according to state news agencies.

Half of the drones were destroyed over the Kursk region close to the border with Ukraine; the rest were downed over the Bryansk, Smolensk, Oryol and Belgorod regions, the TASS news agency reported. Regional governors reported no damage.

However, footage from Tver shared on social media showed huge blasts and fires igniting around Toropets. Some residents were evacuated, according to regional authorities. It remains unclear if there were any casualties.

Tver’s region governor, Igor Rudenya, said on Telegram that a partial evacuation order was issued as air defences and responders were “working to contain the fire” caused by falling debris.

Students in the nearby Zapadnodvinsky district were told to stay at home and study online. The regional administration also announced power outages.

The Toropets arsenal, located near the site of the reported missile attack, stores missiles, ammunition and explosives, according to Rossiyskaya Gazeta, the Russian government’s official newspaper.

Built in 2015 for $39m, the arsenal is also equipped with cold and heated rooms, electrical substations, treatment facilities, water and fuel storage tanks and more than 100 fire water ponds, the outlet reported.

Dmitry Bulgakov, former deputy defence minister, told Russian army news outlet Zvezda in 2018 that the full load of each storage facility of the arsenal is up to 240 tonnes.

The arsenal also has facilities to accommodate up to 200 servicemen, according to the RIA state news agency.

Air war

Ukraine has ramped up its drone production over the past two years. It is now using them to increase attacks on Russia, striking deeper into its neighbour’s territory, in particular targeting military and energy infrastructure, in a bid to disrupt Moscow’s war machine and to try to impress upon the Russian public that it is not immune to the effects of the war.

Ukraine’s biggest-ever drone attack targeted the Russian capital in September, killing at least one person, wrecking homes and disrupting flights at Moscow’s airports.

Russia continues to use air strikes to target Ukraine, particularly aiming at energy infrastructure in advance of the winter.

On Wednesday, it targeted energy facilities in Ukraine’s northeastern city of Sumy, just across the border from Kursk, and killed one person in the central city of Kropyvnytskyi, regional authorities said.