The Ukrainian president was guarded by tight security as he saw the scene of the appalling atrocities.
Mr Zelensky spoke to local residents about the horrors inflicted on their community by Mr Putin’s forces.
Earlier he vowed Putin and his troops who brought such “evil to our land” would be punished for war crimes which have appalled the world.
As more harrowing footage emerged of civilians murdered in Bucha, near Kyiv, Britain condemned the “whole new world of horror” unleashed by the Russian president and vowed to lead the global response to force him to end his barbaric invasion.
Cabinet ministers called for tougher sanctions against the Putin regime, as well as more military, economic and diplomatic support for Ukraine. Its prosecutor-general, Iryna Venediktova, said the bodies of 410 civilians had been found in towns near the capital, which were recently retaken from Russian troops.
Tetyana Volodymyrivna, who lives in Bucha, described the horror of finding her murdered husband. “I recognised him by his sneakers, his trousers. He looked mutilated, his body was cold,” she said. In a late-night address to the Ukrainian nation, Mr Zelensky said “concentrated evil has come to our land”.
He stressed that “every crime of the occupiers on the territory of our state” would be investigated. Vowing that war criminals would be brought to justice, he added: “Everyone guilty of such crimes will be entered in a special Book of Executioners… will be found and punished.” Speaking to CBS News he described the killings as “genocide” and said the Russian invasion involved “the torture of the whole nation”.
He added: “Indeed, this is genocide. The elimination of the whole nation and the people. We are the citizens of Ukraine. We have more than 100 nationalities. This is about the destruction and extermination of all these nationalities.” He emphasised that a special justice administration would be set up, involving international prosecutors and judges, adding: “The world has seen many war crimes. The time has come to make the war crimes committed by Russian troops the last such evil on Earth.”
However, it was still not clear how Mr Putin and his military commanders would be brought to justice for the atrocities committed in Ukraine.
In London, Cabinet minister Simon Hart said there was a need for a “common endeavour” from the West to pile pressure on the Kremlin to stop the military onslaught, which Russian defence chiefs are now refocusing on the Donbas region in eastern Ukraine, and to increase military, economic and diplomatic support for Ukraine.
“Clearly, in any situation like this, a negotiated settlement is where everybody attempts to aim, but we are in a whole new world of horror now and therefore we have to, at this immediate moment, provide all of the help and support that we can, in the numerous ways we can and continue to lead and inspire the international response,” he told Talk Radio.
Mr Zelensky has already praised Boris Johnson for seeking to galvanise an international response to Mr Putin’s invasion which has left thousands, if not tens of thousands, of civilians dead including in the besieged city of Mariupol.
Speaking on Sky News, Welsh Secretary Mr Hart said: “This is not just the UK. This about leading a world response. If the response is to be effective, it needs the West and many, many nations to come together in that common endeavour.”
He added that Britain was ready to do its best to provide different weapons to Ukraine, as its demands changed, or the finance to obtain them from another source.
On tightening sanctions on Mr Putin’s regime, he added: “Now, is not the moment to sit back and say we have done enough.” In France, President Emmanuel Macron said a new round of sanctions targeting Russia was needed and that there were clear indications Russian forces were responsible for the killings of civilians in Bucha.
Mr Macron told France Inter radio: “What happened in Bucha demands a new round of sanctions and very clear measures.” Those new sanctions should target coal and oil, said Mr Macron, who faces a re-election battle this month.
The Kremlin, which denied it was planning an invasion of Ukraine, has now also denied its forces were responsible for the deaths of civilians in Bucha and said Ukraine had staged a performance for the Western media.
But the assertion flew in the face of the shocking footage, pictures and reports of civilians, some with their hands tied behind their backs, with signs of torture and having been shot in the head, as well as mass graves being discovered. The bodies of several women were also found dumped at the side of the road.
Poland’s prime minister Mateusz Morawiecki accused Germany, which is heavily reliant on Russian gas, of having been the main roadblock to imposing tougher sanctions on Russia.