A factory deep inside Russia that was accused of assembling Iranian attack drones for use against Ukraine came under attack early Tuesday, injuring at least 12 people, according to local authorities.

Russia’s third-biggest oil refinery was also hit in the brazen, early-morning attack in Tatarstan, which is at least 800 miles from the frontline in Ukraine, the deepest of any attack in Russia since the war began.

While Kyiv has not officially taken credit, an unnamed source in Ukraine’s military was quoted telling Ukrainska Pravda and AFP that the attack was carried out by military intelligence using drones that resemble light aircraft. Footage purported to be of the attack in Yelabuga, in Russia’s Republic of Tatarstan captured the…