At least 13 people were killed, including a child, and 39 injured in a Ukrainian drone attack on industrial and civilian targets in the city of Nizhnekamsk, authorities said yesterday, one of the heaviest civilian tolls in Russia in months.

The attack in the Tatarstan region, about 800 km east of Moscow, also hit a major oil refinery, according to Russian media reports.

Russian investigators said they had opened a criminal case into what they qualified as a terrorist attack, saying in a statement that Ukraine had struck residential areas and that a child was among those civilians killed.

The region’s oil refinery, one of Russia’s most technologically advanced, was hit in the attack, Russian media reported.

Russia’s defence ministry said it shot down 456 Ukrainian drones fired overnight, reports Reuters.

Meanwhile, a Russian artillery strike on Ukraine’s northeastern Kharkiv region killed five people, regional prosecutor’s office said yesterday.

“On August 10, Russian forces carried out a massive artillery strike on the residential area of the village of Bugaivka in the Chuguiv district. Various houses were destroyed as a result of the enemy attack. Five people were killed,” the prosecutor’s office said in a statement on Telegram.

Ukraine’s air force said Russia fired 126 drones in its overnight attack, reports AFP.

A woman was also killed in a Ukrainian attack on the Russian border region of Belgorod, and a man was killed in a Russian drone strike on a taxi in the frontline Kherson region, officials there said.