Reuters could not independently verify the allegations.
In the village of Nova Basan, northeast of Kyiv, which was among those retaken by Ukrainian forces, the body of a man lay next to the carcass of a car. A woman wept as men brought a coffin to remove the body.
The village showed signs of heavy fighting, with collapsed buildings and the wreckage of tanks and armoured vehicles strewn around. Another dead body, apparently that of a Russian soldier, lay near a destroyed armoured personnel carrier.
Maksim Levin, a Ukrainian photographer and videographer who was working for a Ukrainian news website and was a long-time contributor to Reuters, was killed while covering the war.
Russia denies targeting civilians in what President Vladimir Putin calls a “special military operation” aimed at demilitarising and “denazifying” Ukraine.
Ukraine calls it an unprovoked war of aggression and Western countries have imposed sweeping sanctions in an effort to squeeze Russia’s economy.
In encircled Mariupol, Russia’s main target in Ukraine’s southeastern region of Donbas, tens of thousands of civilians remained trapped with scant access to food and water.
A convoy of about 54 Ukrainian buses and other private vehicles, accompanied by a team from the International Committee of the Red Cross (ICRC), was renewing its attempt to organise a mass evacuation from the city after turning back on Friday.
ICRC spokesperson Ewan Watson said the team had not yet reached Mariupol, adding they left the city of Zaporizhzhia on Saturday morning and would spend the night en route.
Some civilians who have escaped Mariupol and reached Zaporizhzhia said Russian soldiers repeatedly stopped them to check for the presence of Ukrainian fighters as they fled.
“They stripped the men naked, looked for tattoos,” said Dmytro Kartavov, a 32-year-old builder, adding that the troops paid particular attention to the men’s knees.
“I work, I do repairs, naturally my knees – these are working knees. They say – (you) climbed trenches, dug, and the like.”
Pope Francis came the closest he has yet to criticising Vladimir Putin over the invasion. He did not name the Russian president but said a “potentate” was fomenting conflicts for nationalist interests.
“Once again, some potentate, sadly caught up in anachronistic claims of nationalist interests, is provoking and fomenting conflicts, while ordinary people sense the need to build a future that will either be shared or not be at all,” he said during a visit to Malta.
Even as Russian forces pulled back from some northern areas, Ukrainian officials reported missile strikes on targets in various parts of the country.
The governor of south-central Dnipro region, Valentyn Reznichenko, said a Russian rocket hit a rail line, badly damaging the tracks and suspending train traffic in the area. He did not say if there were any casualties.
In the early hours, Russian missiles hit the cities of Poltava and Kremenchuk in central Ukraine, Dmitry Lunin, head of the Poltava region, wrote in an online post.
Before dawn, as sirens sounded across Ukraine, the Ukrainian military reported Russian air strikes on the cities of Severodonetsk and Rubizhne in the Luhansk region.