The Bucha massacre is the "tip of the iceberg", Ukrainian officials have warned as more allegations of Russian atrocities emerged.
In Borodyanka, a town 22km to the west, the situation is "much worse", the country's top prosecutor said yesterday, while the mayor of Mariupol estimated that 90 per cent of the buildings in his city had been destroyed and thousands of people killed by Russian bombing.
Volodymyr Zelenskyy appeared emotional on a visit to Bucha, near Kyiv, where his forces found hundreds of murdered civilians over the weekend after the Russian army had retreated.
He accused Moscow of a "genocide" and said that it would now be harder to forge a peace deal to end the war.
"You can see around you what was done to this modern town. That's a characteristic of Russian soldiers: they treat people worse than animals," the Ukrainian President told reporters. "This is real genocide, what you have seen here today."
Ukrainian soldiers found mass graves holding up to 300 civilians when they moved into the town. Many had their hands tied behind their backs and had been shot in the head. Russian forces had occupied Bucha for a month.
The images shocked the world but officials have said these were just the first civilian murders that the Russian retreat would reveal.
Iryna Venediktova, the Ukrainian prosecutor-general, said the atrocities in Borodyanka were likely to overshadow those in Bucha and that Russia had "committed crimes against humanity".
"In terms of human casualties, the worst situation is in Borodyanka. There's a lot to process," she said.
Meanwhile, Vadym Boichenko, the mayor of Mariupol, the embattled port city on the south coast, said that almost every building had been destroyed.
"The horrors that we've seen in Bucha are just the tip of the iceberg of the crimes committed by the Russian army in the territory of Ukraine so far," he said. "And I can tell you without an exaggeration, but with great sorrow, that the situation in Mariupol is much worse."
Thousands of people have died, many of them civilians, and millions of people have been forced to flee from their homes since Vladimir Putin began his invasion on Feb 24. He expected an easy victory but stiff Ukrainian resistance has turned the war into one of attrition.
The West has punished Russia with sanctions and funnelled arms to Ukraine but Zelenskyy blamed European leaders for encouraging Russian aggression with their policies of "appeasement" after it annexed Crimea in 2014.
"I think that they need to come here and see what flirting with the Russian Federation amounts to," he said on his visit to Bucha. The next round of peace talks between Ukraine and Russia had been scheduled for this week.
Last week, both sides said they had made progress towards a peace deal, with Ukraine agreeing not to join Nato and Russia appearing to pull back its forces. But the discovery of the murdered civilians and news from eastern Ukraine that Russian forces appear to be preparing for a major attack has dented hopes of a deal.
The invasion has turned Russia into a pariah state and, despite being labelled as "traitors" by Putin, thousands of Russians have fled the worsening economic conditions and draconian controls, which include not being able to refer to a "war" in public.
The Kremlin has denied accusations of genocide in Bucha and has instead said that the dead civilians were killed by Ukrainian shells in a plot hatched by the CIA and MI6.
"From what we have seen, our experts have identified signs of video falsification and other fakes," said Dmitry Peskov, a Kremlin spokesman.
Meanwhile, Israeli media said Russian oligarch Mikhail Prokhorov, who had been considered close to the Kremlin, was the latest high-profile businessman looking to move abroad.
Sanctioned by the West, he flew to Israel last month and has now reportedly applied for residency. He is the 12th richest man in Russia, with an estimated fortune of $16 billion.