Russia and Ukraine have accused each other of violating separate ceasefires declared by each side to cover the celebrations of the Soviet Union's victory over Nazi Germany.
The Russian defence ministry reported more than 1,000 violations in the conflict zone, while Moscow's mayor said the city had been targeted by drones since the ceasefire began at midnight local time (21:00 GMT Thursday).
Ukraine also said Russia had continued to strike its positions since that time.
Russian President Vladimir Putin announced a ceasefire for 8-9 May ahead of Victory Day celebrations on Saturday. Kyiv had earlier called for an indefinite truce, starting 6 May.
Russia has warned Ukraine not to try to attack the Victory Day parade in Red Square.
