The number of civilians killed or injured in Ukraine in March was 604, according to the UN, which has a human rights monitoring team in the country.
The figure is 20% higher than February's.
The UK's Ministry of Defence, highlighting the numbers in its daily update, said 57 children were reported killed in March - "double the previous month".
Their deaths have been "attributed directly to Russian use of aerial munitions", the MoD said.
