Officials say a Ukrainian drone has struck an industrial plant deep inside Russia, injuring several people and causing a fire.

One million Russian soldiers being killed or injured is a stunning and grisly milestone,” the Center for Strategic and International Studies (CSIS) noted earlier this month, as Russian fatalities in Ukraine topped the seven-figure threshold.

The overnight attack was one of the largest on Ukraine and included strikes in the western part of the country, which is hit less often.