Ukraine’s foreign minister on Sunday accused Russian forces of carrying out a “massacre” in the town of Bucha, while US secretary of state Antony Blinken described images of dead bodies there as “a punch in the gut”.

Russia’s defence ministry denied the Ukrainian allegations, saying footage and photographs showing bodies in Bucha were “yet another provocation” by Kyiv.

After Ukraine said on Saturday its forces had reclaimed control of the whole Kyiv region, images of corpses in civilian clothes left behind by departing Russian troops prompted calls from officials in Ukraine and Europe for tougher sanctions on Russia.

The outrage in Ukraine and abroad added to pressure on Russian President Vladimir Putin because it increased the likelihood of further western sanctions.

“We are still gathering and looking for bodies, but the number has already gone into the hundreds,” foreign minister Dmytro Kuleba said, according to his ministry.

“Bodies lie on the streets. They killed civilians while staying there and when they were leaving these villages and towns,” Kuleba said.

He called on G7 nations to impose “devastating” new sanctions on Moscow and urged the International Criminal Court to collect evidence of what he called Russian war crimes.

In Russia’s first public comment on the allegations, the defence ministry described photos and videos from Bucha as “another staged performance by the Kyiv regime for the western media”.

“During the time that Russian armed forces were in control of this settlement, not a single local resident suffered from any violent actions,” it said.

On Saturday, Reuters saw bodies in a mass grave and still lying on the streets, while on Sunday the mayor of Bucha, Anatoliy Fedoruk, showed reporters two corpses with white cloth tied around their arms, one of which appeared to have been shot in the mouth.

The foreign ministers of Germany, France and Britain and the European Union’s foreign policy chief were among those expressing outrage over the reports from Bucha.

Oleksiy Arestovych, an aide to Ukrainian President Volodymyr Zelensky, said Ukrainian troops had found the bodies of women who had been raped and set alight as well as the bodies of local officials and children.

In Bucha, 37km northwest of Kyiv city centre, town mayor Fedoruk said 300 residents had been killed during a month-long occupation by the Russian army.

Fighting was reported on Sunday in several parts of Ukraine. The governor of the eastern Donetsk region said shelling had continued throughout the night and day.

Missiles struck near the southern port of Odesa, with Russia saying it had destroyed an oil refinery used by the Ukrainian military. The Odesa city council said “critical infrastructure facilities” were hit.