A refining and petrochemical plant in Nizhnekamsk (stock photo)
At least 13 people have been killed in a Ukrainian drone strike on the Russian republic of Tatarstan, officials have said.
One child was among the victims with 75 more people injured, Russian authorities said, in one of the deadliest single attacks on Russia since the start of Moscow's full-scale war in Ukraine.
Kyiv has not yet commented on the strike on the city of Nizhnekamsk, which is more than 1,100 kilometres (680m) from the Ukrainian border.
Ukraine's Armed Forces confirmed Nizhnekamsk's Tanevo oil refinery had been hit, while Ukrainian defence technology manufacturer FirePoint said its FP-1 drones had been used in the attack.
The strike lasted several hours overnight and into the morning, local sources say. Oil refineries in Nizhnekamsk had already been hit on 12 June.
Verified images on social media show large plumes of smoke and flames rising into the sky in daytime, with air raid sirens howling in the background.
Kyiv has recently stepped up its strikes on facilities it says contribute revenue and logistics to Russia's war on Ukraine.
"The facilities Ukraine targets are used to carry out attacks against Ukraine, manufacture weapons, support Russia's war effort," said Andriy Kovalenko, head of the Ukraine's Centre for Countering Disinformation.
Moscow confirmed industrial facilities were targeted but added residential areas were struck, too.
"Civilian individuals who were not involved in any military operations were present," Russia's Investigative Committee said. The BBC has not independently verified this information.
The head of Tatarstan, Rustam Minnikhanov, confirmed the strike and shared his condolences with the families of the deceased.
"This is a tremendous pain for all of us," said Nizhnekamsk mayor Radmir Belayev.
A period of mourning has been declared in Tatarstan.
Ukraine's Kovalenko said "every civilian death in Russia is on [President Vladimir] Putin" and that "Russians should direct their grievances at Putin and at the decisions made within their own country".