WARNING: Disturbing content
Russian soldiers locked 25 Ukrainian girls and women in a basement in Bucha and systematically raped them, Ukraine’s ombudsman for human rights has said.
Nine of those victims, aged between 14 and 24, are now pregnant, Lyudmyla Denisova said.
"Russian soldiers told them they would rape them to the point where they wouldn't want sexual contact with any man, to prevent them from having Ukrainian children,” she told the BBC.
Denisova’s claims, which remain unverified, were given credence by Ukrainian president Volodymyr Zelensky, who said later on Tuesday that investigators had received reports of "hundreds of cases of rape" in areas previously occupied by Russian troops, including sexual assaults of small children.
"In areas freed from the occupiers, the recording and investigation of war crimes committed by Russia continues," Zelensky told Lithuanian lawmakers via video link.
"New mass graves are found almost daily.
"Testimonials are being collected. Thousands and thousands of victims. Hundreds of cases of torture. Bodies continue to be found in drains and cellars," he added.
"Hundreds of cases of rape have been recorded, including those of young girls and very young children. Even of a baby!"
The claims will add further weight to demands that Russian forces and their leader, president Vladimir Putin, to be charged with war crimes and crimes against humanity.
Evidence of atrocities in Bucha has continued to emerge in the weeks since hundreds of civilians were found dumped in mass graves in the Ukrainian town. Russia has since been expelled from the United Nations human rights council.
Denisova is currently documenting cases of sexual crimes committed during the war and said that reports were flooding in on support lines and messaging app Telegram.
She listed a number of allegations that she had received: from claims that a 14-year-old girl had been gang-raped by five men and is now pregnant, to a report that soldiers had raped a boy aged 11 while his mother watched, tied to a chair.
“The level of brutality of the army of terrorists and executioners of the Russian Federation knows no bounds – raped children,” she wrote on Facebook.
International humanitarian law prohibits the killing, rape, sexual violence, torture or inhumane treatment of civilians or captured soldiers. Any breach of those laws is considered a war crime. Commanders of troops who commit such atrocities are also considered guilty if they knew or should have know about such crimes but did not stop them or punish perpetrators.
'Take your clothes off or I'll shoot you'
On Tuesday, the BBC also reported the claims of a 50-year-old woman just outside Kyiv, who said she was raped by a Russian soldier.
"At gunpoint, he took me to a house nearby. He ordered me: 'Take your clothes off or I'll shoot you.' He kept threatening to kill me if I didn't do as he said. Then he started raping me," she told the BBC.
Other Russian soldiers who entered the house as she was being raped took the aggressor away, she said. When she returned home, she found her husband shot in the abdomen. He died two days later.
A police chief in the Kyiv region told the BBC that they were investigating a similar case in another village outside Kyiv.
Russian soldiers had entered the house belonging to a couple and their young child, shot the husband and repeatedly raped the wife, Andrii Nebytov said.
“They threatened that if she resisted they would harm her little boy. To protect her child she didn't resist."
When the soldiers left, they shot the family’s dogs and burnt the house down, he said.
Russia says US helping with 'false information'
Russia has staunchly denied all allegations of war crimes and said that the claims are part of an effort to depict Russian soldiers in a bad light.
The country’s defence ministry has said its troops are taking “unprecedented measures” to save civilians and claimed that the United States is helping Ukraine disseminate false information.
Russia’s deputy UN ambassador Gennady Kuzmin accused Ukraine and its allies of “a clear intention to present Russian soldiers as sadists and rapists.”
Allegations of Russian atrocities have been referred to the International Criminal Court, which is investigating the claims and gathering evidence. France has also sent a team of police officers and investigators to Ukraine to investigate similar claims.