Ukraine's president has vowed to identify Russian troops behind alleged war crimes, saying that Moscow "cannot deceive the whole world" despite its attempts to "distort the facts".

Russian soldiers have been accused of carrying out "genocide" amid evidence of mass graves and torture as Kremlin forces pull back from Kyiv.

More than 300 bodies have been discovered in the town of Bucha, around 16 miles from Kyiv, including those of four people who had their hands tied behind their backs in the basement of what was a children's holiday camp.

Giving a presidential address, Volodymyr Zelenskyy said that civilians in liberated areas of the Kyiv, Chernihiv, and Sumy regions had been subjected to treatment "not seen even during the Nazi occupation 80 years ago".

Russian troops 'will try to hide the traces of their crimes'

Pledging to bring Russian troops to account "for every crime they commit", Mr Zelenskyy warned that "the occupiers will try to hide the traces of their crimes".

"They are already launching a false campaign to conceal their guilt in the mass killings of civilians in Mariupol," he said.

"They will do dozens of stage interviews, re-edited recordings, and will kill people specifically to make it look like they were killed by someone else."

"[Russia is] trying to distort the facts," he added. "But, as then, they will not succeed. They will not be able to deceive the whole world.

"The time will come when every Russian will learn the whole truth about who of their fellow citizens killed. Who gave orders. Who turned a blind eye to the murders.

"We will establish all this. And make it globally known."

'You could have helped,' Zelenskyy tells Western leaders

Mr Zelenskyy renewed his call for more lethal aid from Western leaders, questioning why they had been gripped by "doubts and indecision".

He said: "If we had already got what we needed - all these planes, tanks, artillery, anti-missile and anti-ship weapons, we could have saved thousands of people. I do not blame you - I blame only the Russian military. But you could have helped."

On Monday, Mr Zelenskyy visited Bucha for his first reported trip outside the capital since the Russian invasion began nearly six weeks ago.

Later today he will address the UN Security Council on allegations of war crimes in the town and other parts of Ukraine.

Moscow has categorically denied killing civilians in Bucha, claiming the allegations are "stage-managed anti-Russian provocation."

Footage of bodies lying in the streets of Bucha and the discovery of what Ukrainian prosecutors described as a "torture chamber" have led to international condemnation, with US President Joe Biden calling for a war crimes trial.

Calling Russian president Vladimir Putin "brutal", Mr Biden said: "What's happening in Bucha is outrageous and everyone sees it."

Germany said it had expelled 40 Russian envoys over the atrocities in Bucha, while France says it will kick out 35 diplomats.

Meanwhile, EU leaders say the bloc will impose further sanctions on Russia and pledge more support for Ukraine.