The largest blaze erupted on a warehouse premise and spanned an area of about 3,000 square metres, the State Emergency Service of Ukraine said, adding that firefighters were on the scene.

The agency said that four people were injured in Kharkiv, including a child, according to preliminary information.

Ukraine's air force said Russia deployed 13 Shahed combat drones, as well as four converted S-300 anti-aircraft missiles.

The Air Force claimed to have intercepted all the drones. But the mayor of Kharkiv, Ihor Terekhov, said two had struck the city.

There were also two people injured from Russian strikes in the eastern Dnipropetrovsk region. An infrastructure site and several residential buildings were damaged, Governor Serhiy Lysak said in a Telegram post.

Russia's full-scale war against Ukraine has been going on for more than 800 days.

At the start of the war, Russian forces tried unsuccessfully to occupy the city, located near the Russian border. Kharkiv has been attacked with missiles and drones practically every day for months, and there are fears Russia could be planning a fresh summer campaign to capture it.