Explosions echoed over Kiev on Tuesday during a rare daytime Russian drone attack on the capital, after the two sides launched strikes that left six dead.
A major oil refinery in southern Russia was also set ablaze, triggering a local state of emergency as thick black smoke billowed over the coastal town of Tuapse.
Russia has pummelled Ukrainian cities since the war began more than four years ago, mainly by launching long-range aerial barrages at night.
AFP journalists in Kiev heard air raid sirens ring out and at least one loud boom over the city shortly after 0215 PM (1115 GMT).
Exchange of aerial attacks
City officials announced that air defence systems were operating against Russian drones flying over the city and that two people were hurt in the attack.
