UN Secretary-General Antonio Guterres on Monday called for an independent investigation into the alledged killings of hundreds of civilans in Bucha, outside the Ukrainian capital Kyiv.

"I am deeply shocked by the images of civilians killed in Bucha, Ukraine," Guterres wrote on his official Twitter account. "It is essential that an independent investigation leads to effective accountability."

At least 280 people, including children, were found dead in Bucha, Mayor Anatoly Fedoruk told AFP by phone on Saturday.  The Ukrainian army retook control of the town from the Russian military, which is some 28 km northwest of Kyiv.

Ukrainian President Volodymyr Zelenskyy on Monday visited the town, calling the killings "a war crime."

The Kremlin has denied all accusations, suggesting images of corpses were "fake."

"Experts at the Ministry of Defense have identified signs of video fakes and various fakes," he told reporters on Monday, adding that the facts and chronology of the events in Bucha did not support Ukraine's version of events.

According to the latest update from the UN human rights office, 3,455 civilian casualties have been recorded in Ukraine. The UN has urged an immediate ceasefire, vowing to "do everything in its power to support people whose lives have been overturned." 

(Cover: File photo of UN Secretary-General Antonio Guterres. /CFP)