Three people were killed and many more wounded when a shell hit a hospital in the rebel-held city of Donetsk in eastern Ukraine.
Bodies could be seen under blankets outside the building after the attack.
Violence has surged in recent weeks, and the pro-Russian rebels are trying to encircle the key town of Debaltseve, north-east of Donetsk.
EU foreign policy chief Federica Mogherini appealed for a truce to allow civilians to leave the area.
Her words echoed an appeal by international observer group the OSCE on Tuesday for a three-day ceasefire around the town.
According to Amnesty International, 7,000 people remain in Debaltseve, a major road and rail hub, out of an original population of 25,000 a few days ago.
The separatists have already captured Donetsk airport from government forces in the past few weeks.
The hospital in the south-western Kirovskiy area of Donetsk was being used as an outpatient clinic at the time of the attack and many of the injured were patients and staff, BBC correspondent Olga Ivshina reports from the scene.
The sound of shelling could still be heard two hours later, she said.