Ukraine war: International outrage grows over civilian killings in Bucha

US President Joe Biden has called for Russian President Vladimir Putin to be tried for war crimes as evidence emerges of atrocities allegedly committed by Russian forces in Ukraine.

There is mounting international anger over the alleged killing of civilians in Bucha, a town near the capital Kyiv.

The US says it's supporting a team of international prosecutors heading to Bucha to collect evidence.

Without evidence, Russia said images of atrocities had been staged by Ukraine.

The Ukrainian government has started a war crimes investigation after it said the bodies of 410 civilians had been found in areas around Kyiv. Some were discovered in mass graves while others had their hands tied and had apparently been shot at close range.

"This guy is brutal," Mr Biden said of the Russian president, adding that he wanted more sanctions against the Kremlin.

"You saw what happened in Bucha - he is a war criminal... but we have to gather all the detail so this can have a war crimes trial," he added.

The US state department said it had credible reports of rape, torture and summary executions carried out by Russian forces as part of what it described as a "broader, troubling campaign" by Moscow.

At the request of Ukraine, the international prosecutors will support the prosecutor general of Ukraine's war crimes unit.

"There are reports and images of a nightmare litany of atrocities," said state department spokesman Ned Price.

The Pentagon said it was "fairly obvious" that Russia had been behind the atrocities in Bucha, but that more investigation was needed to ascertain which units were responsible.

Ukrainian President Volodymyr Zelensky visited Bucha and accused Moscow of genocide and war crimes.

France and Germany are expelling Russian diplomats in response to the discoveries in Bucha.

German Foreign Minister Annalena Baerbock said the expulsion of 40 envoys was in response to the "unbelievable brutality" the Kremlin had unleashed in Ukraine.

The French government said it would expel "many" Russian staff, but didn't specify the exact number.

Lithuania said it was expelling the Russian ambassador, citing atrocities it says have been committed by Russian troops in Ukraine.

Moscow's ambassador to the UN said Russia would present "empirical evidence" to the UN Security council demonstrating that Western statements on events at Bucha were lies.

At a press conference in New York, Vasily Nebenzya accused Ukraine and its "Western sponsors" of fabricating evidence and carrying out a false flag attack on its own people.

In Bucha, witnesses have described Russian soldiers firing on men fleeing after refusing to allow them to leave through humanitarian corridors.

At least 20 dead men were found lying in the street, many of them with extensive wounds. Some had been shot through the temple, as if executed, while others had clearly been run over by tanks.

Satellite images taken by Maxar show a 14m (45ft) mass grave in the city near the church of St Andrew and Pyervozvannoho All Saints.