Shocking images have shown mass graves and dead civilians lying in the streets in the town of Bucha, after Ukrainians liberated it from Russian forces.
Warning: This article contains images and details readers might find distressing.
Authorities say the proof that civilians have been killed is evidence that Russian forces have committed war crimes during their invasion of Ukraine.
The images and reporting coming out of Bucha has prompted US President Joe Biden to call for Russian President Vladimir Putin to face trial, and Defence Minister Peter Dutton has said Australia would support any war crimes investigation into the Russian leader.
But Moscow strongly denies it has killed civilians during the ongoing conflict.
So, what can we be sure of? Let's take a look at what we know.
Bucha was liberated by Ukrainian forces. Then bodies were discovered
Earlier this week, the Ukrainian government said its forces had regained control of the entire Kyiv region, five weeks after Russia launched its invasion.
Authorities said towns near the capital, such as Bucha, Irpin and Hostomel, had been reclaimed.
But as Russian forces withdrew, reports began to emerge of bodies lying in the streets in Bucha.
Ukrainian authorities said the bodies of at least 410 civilians were found in areas on the outskirts of Kyiv.
Images from around Bucha, seen by the ABC, showed many of the bodies have been lying in the open for weeks, during the time Russian forces had occupied the town.
There were grisly images of battered or burned bodies left out in the open or hastily buried.
Associated Press journalists reported that many victims appeared to have been shot at close range, some in the head. At least two had their hands tied.
A mass grave was discovered in a churchyard
Satellite imagery provided by Maxar Technologies shows the grounds behind the Church of St Andrew and Pyervozvannoho All Saints below.
On March 10, a visibly lighter patch of earth appeared to show an excavation site in the south-west corner of the churchyard.
On March 31, an approximately 13.7-metre-long trench could be seen.
The satellite images were verified by AP journalists at the scene who witnessed bodies wrapped in black plastic piled at one end of the mass grave.
Father Andrii Galavin said with the morgue full and the cemetery impossible to reach, the churchyard was the only place to keep the dead.
Residents spoke of their slain loved ones
In a statement, the Ukrainian prosecutor-general's office said the bodies of five men with their hands bound were found in the basement of a children's sanatorium where civilians were tortured and killed.
AP journalists saw dozens of bodies in Bucha, including at least 13 in and around a building that local people said Russian troops used as a base.
Three other bodies were found in a stairwell, and a group of six were burned together.
Tanya Nedashkivs'ka said she buried her husband in a garden outside their apartment building after he was detained by Russian troops.
His body was one of those left heaped in a stairwell.
"It's me talking, a Ukrainian woman … a mother of two kids and one grandchild. For all the wives and mothers, make peace on Earth so no-one ever grieves again."
Another Bucha resident, Volodymyr Pilhutskyi, said his neighbour, Pavlo Vlasenko, was taken away by Russian soldiers because the military-style pants he was wearing and the uniforms that Mr Vlasenko said belonged to his security-guard son appeared suspicious.
When Mr Vlasenko's body was later found, it had burn marks from a flamethrower, his neighbour said.
"I came closer and saw that his body was burnt," Mr Pilhutskyi said.
"They didn't just shoot him."
Now the Ukrainian President has left the safety of his headquarters to witness the carnage
Ukrainian President Volodymyr Zelenskyy has left Kyiv for his first reported trip since the war began to see for himself what he has called the "genocide" and "war crimes" in Bucha.
Mr Zelenskyy and other Ukrainian authorities have warned the full extent of the horrors is yet to emerge.
"This is only one town, one of many Ukrainian communities which the Russian forces managed to capture," Mr Zelenskyy said.
Ukrainian prosecutor-general Iryna Venediktova told Ukrainian TV that a "similar humanitarian situation" to Bucha existed in other parts of the country where Russian forces recently left, such as the areas around the northern cities of Sumy and Chernihiv.
She also said the situation in Borodyanka, which is further from Kyiv and was also held by Russian forces until recently, might be even worse.
The same has been said about the southern city of Mariupol.
"I can tell you without exaggeration but with great sorrow that the situation in Mariupol is much worse compared to what we've seen in Bucha and other cities, towns, and villages nearby Kyiv," Ukrainian Foreign Minister Dmytro Kuleba said.
Meanwhile, Russia continues to deny evidence of war crimes
In his nightly video address, Mr Zelenskyy pledged that Ukraine would work with the European Union and the International Criminal Court to identify Russian fighters involved in any atrocities.
"The time will come when every Russian will learn the whole truth about who among their fellow citizens killed, who gave orders, who turned a blind eye to the murders," Mr Zelenskyy said.
Russian Foreign Minister Sergey Lavrov has dismissed the scenes outside Kyiv as a "stage-managed anti-Russian provocation".
Kremlin spokesperson Dmitry Peskov has also sought to cast doubt on the images coming out of Bucha, saying they contain "signs of video forgery and various fakes".
ABC/wires
