The UN human rights office (OHCHR) said on Saturday that at least 847 civilians had been killed and 1,399 wounded in Ukraine as of March 18.
Most of the casualties were from explosive weapons such as shelling from heavy artillery and multiple-launch rocket systems, and missile and air strikes, OHCHR said.
The real toll is thought to be considerably higher since OHCHR, which has a large monitoring team in the country, has not yet been able to verify casualty reports from several badly hit cities, it said.
Kyiv city authorities on Saturday said 228 people had been killed in the capital since Russia's invasion of Ukraine began, including four children.
A further 912 people have been wounded, the Kyiv city administration said in a statement.