Volodymyr Zelenskyy to address UN Security Council on Tuesday

Ukrainian president says there may be more mass civilian casualties in other occupied towns

Ukrainian President Volodymyr Zelenskyy in his video address from Kyiv on April 3. AP

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Ukrainian President Volodymyr Zelenskyy said he would address the UN Security Council on Tuesday and predicted worse cases of mass civilian killings by Russian troops would be found.

Tuesday's Security Council session is to consider Ukrainian allegations of civilian murders by Russian troops in Bucha, north-west of Kyiv, after the discovery of hundreds of bodies, some bound and shot at close range.

Russia has categorically denied the accusations, calling them "criminal provocations", and says it will present "empirical evidence" to the Security Council that its forces have not been involved in atrocities.

Mr Zelenskyy has already spoken by video link to more than a dozen assemblies, including the US Congress and the British and European parliaments.

"I would like to emphasise that we are interested in the most complete, transparent investigation, the results of which will be known and explained to the entire international community," he said in his nightly video address early on Tuesday.

In Bucha, where mass graves and bodies were found after Ukraine took the town back from Russian forces, at least 300 civilians had been killed, Mr Zelenskyy said.

"And this is only one town, one of many Ukrainian communities which the Russian forces managed to capture," he said.

"Now, there is information that in Borodyanka and some other liberated Ukrainian towns, the number of casualties of the occupiers may be even much higher."

Ukrainian authorities say they have restored control over all of Kyiv region and other districts after Russia announced it had shifted its aims away from Kyiv and Chernihiv in the north to secure control over the entire eastern Donbas region.

Around Kyiv, Chernihiv and Sumy regions further north and east, "the occupiers did something that the locals did not even witness during the Nazi occupation 80 years ago", Mr Zelenskyy said.

It was in Ukraine's interests to have "thousands of journalists there. As much as possible. Let the world see what Russia has done", he said.

Mr Zelenskyy said Russian forces did not conceal what happened in Bucha but could do so in other places they had occupied.