In the city of Kherson, in southern Ukraine, small drones routinely target ordinary people by dropping hand grenades, and record video documenting their attacks, a U.N. commission reported.

Gun and drone street battles are taking place in the key city of Pokrovsk infiltrated by around 200 Russian soldiers, say Ukrainian defence chiefs. Ukraine is rushing to strengthen its positions in the strategic eastern city in the Donetsk province of the Donbas region.

Russia is trying "to inflict as much damage as possible on ordinary life," said Ukraine's president, Volodymyr Zelensky.