As Ukraine claimed its forces had retaken all areas around Kyiv, the mayor of a liberated town said hundreds of residents had been killed during the month-long Russian occupation

At Bucha, just 37km northwest of the capital, Reuters journalists saw bodies lying in the streets and the hands and feet of multiple corpses poking from a still open grave at a church ground.

As the town’s residents tearfully recalled brushes with death and cursed the departed Russians, Mayor Anatoliy Fedoruk said at least 300 residents had been killed.

Russia denies targeting civilians and rejects war crimes allegations.

Renewed hope of talks

Ukraine’s troops have so far retaken more than 30 towns and villages around Kyiv, Ukrainian officials said on Saturday, claiming complete control of the capital region for the first time since Russia launched its invasion.

Ukrainian negotiator David Arakhamia said the regained territory could put enough pressure on Russia to allow direct talks between Russian President Vladimir Putin and Zelensky.

“The Russian side confirmed our thesis that the draft documents have been sufficiently developed to allow direct consultations between the two countries’ leaders,” Arakhamia said.

Russia has not commented on the possibility.

Among those killed near Kyiv was Maksim Levin, a Ukrainian photographer and videographer who was working for a news website and was a long-time contributor to Reuters.

His body was found in a village north of Kyiv on April 1, the news website LB.ua, where he worked, said on Saturday.

Retreat and redeployment

After five weeks of fighting, Russia has pulled back forces that threatened Kyiv from the north to regroup for battles in eastern Ukraine.

“The whole Kyiv region is liberated from the invader,” Ukrainian Deputy Defence Minister Hanna Malyar wrote on Facebook. There was no Russian comment on the claim, which Reuters could not immediately verify.

President Volodymyr Zelenskiy warned in a video address: “They are mining all this territory. Houses are mined, equipment is mined, even the bodies of dead people.”

Ukraine’s emergencies service said over 1500 explosives had been found in a single day of searching the village of Dmytrivka, west of the capital.

Russia’s defence ministry did not reply to a request for comment on the mining allegations. Reuters could not independently verify them.

In the east, a Red Cross convoy was again seeking to evacuate civilians from the besieged port of Mariupol after abandoning an attempt on Friday over security concerns. Russia blamed the ICRC for the delays.

Mariupol is Russia’s main target in Ukraine’s southeastern region of Donbas, and tens of thousands of civilians there are trapped with scant access to food and water.

Ukrainian President Volodymyr Zelensky said the Russians were leaving mines across “the whole territory” — even around homes and corpses — and creating “a complete disaster”.

“They are mining the whole territory. They are mining homes, mining equipment, even the bodies of people who were killed,” Mr Zelensky said in his nightly video address to the nation.

“There are a lot of trip wires, a lot of other dangers.”

Russian mines left behind in Bucha as the retreat continues. Photo: AAP

Putin ‘a war criminal’

The shocking footage of dead civilians comes as a former United Nations war crimes prosecutor called for an international arrest warrant to be issued for Russian President Vladimir Putin.

Carla Del Ponte was chief prosecutor in tribunals for the former Yugoslavia and Rwanda.

“Putin is a war criminal,” Ms Del Ponte told the Swiss newspaper Le Temps in one of a number of interviews she undertook for the release of her new book.

Ms Del Ponte said she was particularly shocked by the use of mass graves which she said recalled the worst of the wars in the former Yugoslavia.

“I hoped never to see mass graves again,” she told the newspaper Blick.

“These dead people have loved ones who don’t even know what’s become of them. That is unacceptable.”

Other war crimes she identified in Ukraine included attacks on civilians, the destruction of civilian buildings and even the demolishing of entire villages.

She said the investigation in Ukraine would be easier than that in Yugoslavia because the country itself had requested an international probe.

The current ICC chief prosecutor, Karim Khan, visited Ukraine last month.

If the ICC finds proof of war crimes, said Ms Del Ponte, “you must go up the chain of command until you reach those who took the decisions.”

She said it would be possible to bring even Mr Putin to account.

“You mustn’t let go, continue to investigate. When the investigation into Slobodan Milosevic began, he was still president of Serbia. Who would have thought then that he would one day be judged? Nobody,” she told Blick.

More pressure on Mariupol

As the Russians retreat from the north, they appear to be regrouping to double down in the south, including the besieged port of Mariupol which it’s feared could fall to the Russians within days.

In an early morning video address, Ukraine President Volodymyr Zelensky said Russian troops had moved toward Donbas and the heavily bombarded northeastern city of Kharkiv.

“I hope there may still be solutions for the situation in Mariupol,” Mr Zelensky said.

More than 100,000 Ukrainian civilians remained trapped in the city and the Red Cross will again attempt an evacuation.

Encircled since the early days of Russia’s five-week old invasion, Mariupol has been Moscow’s main target in Ukraine’s southeastern region of Donbas.

The Red Cross is trying to evacuate residents trapped in Mariupol. Photo: Getty

The International Committee of the Red Cross (ICRC) sent a team on Friday to lead a convoy of about 54 Ukrainian buses and other private vehicles out of the city, but they turned back, saying conditions made it impossible to proceed.

“They will try again on Saturday to facilitate the safe passage of civilians,” the ICRC said in a statement.

Also, seven humanitarian corridors were planned for Saturday, including one for people evacuating by private transport from Mariupol and by buses for Mariupol residents out of the city of Berdyansk.

-with AAP