Ukrainian authorities have accused the departing forces on Sunday of committing war crimes and leaving behind a "scene from a horror movie".
As images of the bodies — of people whom residents said were killed indiscriminately — began to emerge from Bucha, a slew of European leaders condemned the atrocities and called for tougher sanctions against Moscow.
In a sign of how the horrific reports shook many leaders, Germany's defence minister even suggested that the European Union consider banning Russian gas imports.
So far, the bodies of 410 civilians have been found in Kyiv-area towns that were recently retaken from Russian forces, Ukraine's prosecutor-general Iryna Venediktova said.
Associated Press journalists saw the bodies of at least 21 people in various spots around Bucha, northwest of the capital. One group of nine, all in civilian clothes, were scattered around a site that residents said Russian troops used as a base.
They appeared to have been killed at close range. At least two had their hands tied behind their backs, one was shot in the head, and another's legs were bound.
Ukrainian officials laid the blame for the killings in Bucha and other Kyiv suburbs squarely at the feet of Russian troops, with the president calling them evidence of genocide. But Russia's Defense Ministry rejected the accusations as "provocation".
The discoveries followed the Russian retreat from the area around the capital, territory that has seen heavy fighting since troops invaded Ukraine from three directions on February 24.
Troops who swept in from Belarus to the north spent weeks trying to clear a path to Kyiv, but their advance stalled in the face of resolute defence from Ukraine's forces.
Moscow now says it is focusing its offensive on the country's east, but it also pressed a siege on a city in the north and continued to strike cities elsewhere in a war that has left thousands dead and forced more than four million Ukrainians to flee their country.
Russian troops rolled into Bucha in the early days of the invasion and stayed up to March 30. With those forces gone, residents gave harrowing accounts on Sunday, saying soldiers shot and killed civilians without any apparent reason.
One resident, who refused to give his name out of fear for his safety, said Russian troops went building to building and took people out of the basements where they were hiding, checking their phones for any evidence of anti-Russian activity and taking them away or shooting them.
Hanna Herega, another resident, said Russian troops started shooting at a neighbour who had gone out to gather wood for heating.
"They hit him a bit above the heel, crushing the bone, and he fell down," Herega said. "Then they shot off his left leg completely, with the boot. Then they shot him all over."
Oleksiy Arestovych, an adviser to Ukrainian President Volodymyr Zelenskiy, described bodies lying the streets of the suburbs of Irpin and Hostomel as well as Bucha as a "scene from a horror movie".
He alleged that some of the women found dead had been raped before being killed and the Russians then burned the bodies.
But Russia's Defense Ministry said in a statement that the photos and videos of dead bodies "have been stage managed by the Kyiv regime for the Western media". It noted that Bucha's mayor did not mention any abuses a day after Russian troops left.
The ministry said "not a single civilian has faced any violent action by the Russian military" in Bucha.
Russia also asked for a meeting Monday of the UN Security Council to discuss events in the city, which it blamed on "Ukrainian provocateurs and their Western patrons".
The US and Britain have recently accused Russia of using Security Council meetings to spread disinformation.