KAZAN, Aug. 10 -- Twelve people were killed and 28 others hospitalized, including one child, after Ukrainian drones struck Nizhnekamsk, an industrial city in Russia's Republic of Tatarstan, on Sunday, with regional authorities declaring a day of mourning as emergency crews worked through the aftermath.

The attack struck both industrial and civilian objects, leaving 39 people injured in total, according to Kuznetsov, an aide at Russia's Health Ministry. Nizhnekamsk sits roughly 1,000 kilometres east of the Ukrainian border and is known as a centre of petrochemical production. The strike brought the conflict to a city far removed from the front lines of Russia's military operation in Ukraine.

Tatarstan's regional leadership announced the ...