Ukraine attacked an oil refinery in the city of Syzran in Russia's Samara region overnight, the regional governor said on Wednesday.

"Emergency services are working on the territory of the enterprise. According to preliminary information, there are no casualties," Vyacheslav Fedorishchev wrote on the Telegram messaging app.

He did not specify whether the refinery had been damaged. Baza and Mash Telegram channels reported that the attack caused a fire.

Russia's Defense Ministry said air defense systems had destroyed nine Ukrainian drones overnight - over Bryansk, Tatarstan, and Tula regions and the Black Sea.