Ukraine says Russia has conducted a drone attack in the country, while Ukrainian forces have reportedly attacked oil facilities in Russia.

Forces of the two countries have engaged in fierce battles in Ukraine, mainly on the eastern front.

Ukraine's air force said Russia also attacked urban areas with 21 drones overnight from Tuesday to Wednesday, and that Ukraine destroyed 19 of them.

The mayor of Lviv in western Ukraine said debris from the drones damaged a residential building, a research institute and other structures, and that one injured person was taken to a hospital.

Meanwhile, Ukraine's public broadcaster quoted a source in the country's navy as saying an attack using Ukrainian Neptune anti-ship missiles was carried out early Tuesday morning on oil facilities in the southern Russian region of Krasnodar. The site is more than 250 kilometers from the frontlines.

An oil depot in the Rostov region in southern Russia caught fire in a drone attack, also on Tuesday. Media say Ukraine's security service was involved in the attack.