Ukrainian prosecutors said Thursday they were investigating 10 Russian soldiers for alleged war crimes in Bucha, as the visiting UN chief urged Russia to cooperate with a probe into atrocities. The discovery of bodies in civilian clothes, found on the street or buried in shallow graves in the Kyiv suburb after a Russian retreat shocked the world and prompted allegations of war crimes. Some of the bodies had their hands tied behind their backs. Ukrainian officials accused Russian troops of massacring hundreds of civilians, but Moscow denied any involvement and claimed the images were fakes. The prosecutor general’s office in Ukraine said the servicemen of Russia’s 64th motorised infantry brigade are suspected of “premeditated murder”, cruel treatment and other violations of the laws and customs of war during their occupation in March of Bucha, northeast of Kyiv. Making his first visit to Ukraine since Russia launched its full-scale invasion on February 24, UN Secretary-General Antonio Guterres toured Bucha and two other places where the alleged war crimes occurred, decrying war as “an absurdity in the 21st century” and “evil”. “I imagine my family in one of those houses that is now destroyed and black. I see my granddaughters running away in panic,” the UN chief said in Borodianka, another ruined town, as he backed an International Criminal Court investigation into the accusations. “I appeal to the Russian Federation to accept, to cooperate with the ICC,” he implored the Kremlin. The UN head was also to meet Ukrainian President Volodymyr Zelensky. On Tuesday, he met Russian President Vladimir Putin in Moscow, repeating calls for both countries to work together to set up “safe and effective” humanitarian corridors in war-torn Ukraine. Nearly 5.4 million Ukrainians have fled their country since the invasion, according to the United Nations, and more than 12 million others are displaced internally. “We feel bad, we shouldn’t be standing here,” said Svitlana Gordienko, a nurse forced to relocate to the southern city of Zaporizhzhia, as she queued for food at a humanitarian hub. “We’re left with only one hope: to return home,” added pensioner Galina Bodnya. On Thursday, the White House proposed using assets seized from Russian oligarchs to compensate Ukraine for war-time damage, part of a US attempt to ratchet up economic punishment on the Kremlin. President Joe Biden was to announce the proposed legislation alongside his request to increase funding by Congress for Ukraine’s military later Thursday. Washington has already provided more than $3 billion worth of weaponry to Ukraine since February 24, with the White House now eyeing funding sufficient to last until October. With the war into a third month and claiming thousands of lives, Kyiv has admitted Russian forces are making gains in the east, capturing a string of villages in the Donbas region. The first phase of Russia’s invasion failed to reach Kyiv or overthrow Zelensky’s government after encountering stiff Ukrainian resistance reinforced with Western weapons. The Russian campaign has since refocused on seizing the east and south of the country while using long-range missiles against west and central Ukraine. Ukraine’s Defence Minister Oleksiy Reznikov warned of “extremely difficult weeks” as Moscow tries “to inflict as much pain as possible”. Senior presidential aide Mykhaylo Podolyak insisted Kyiv has the “right” to strike Russian military targets, suggesting direct attacks on facilities inside Russia. The defence ministry in Moscow said its forces had destroyed two arms and ammunition depots in eastern and southern Ukraine overnight with “high-precision missiles”. Russia has targeted Western-supplied arms, as the United States and Europe increasingly heed Zelensky’s call for heavier firepower. In a defiant speech Wednesday, Putin said if Western forces intervene in Ukraine and create “unacceptable threats”, they will face a “lightning-fast” military response. The Kremlin reiterated the warnings Thursday, saying Western arms deliveries “threaten” Europe’s security. Western allies remain wary of being drawn into war with Russia but have stepped up military support.