MOSCOW (REUTERS) - Russia on Sunday (April 3) denied Ukrainian allegations that it had killed civilians in the Ukrainian town of Bucha, describing footage and photographs of dead civilians as a "provocation" and a "staged performance" by Kyiv.

Ukraine has accused the Russian military of massacring residents of Bucha, a town northwest of the capital Kyiv, an area that Ukrainian troops said they recaptured on Saturday.

"All the photos and videos published by the Kyiv regime, allegedly testifying to the 'crimes' of Russian servicemen in the city of Bucha, Kyiv region, are another provocation," Russia's defence ministry said in a statement.

It called the footage "another staged performance by the Kyiv regime for the Western media".

Images of dead civilians strewn across the town prompted Western countries to call for those responsible for war crimes in Ukraine to be punished.

The Russian defence ministry said that all Russian military units had left Bucha on March 30, and that civilians had been free to move around the town or evacuate while it was under Russian control.

"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.

Moscow has previously denied allegations that it has targeted civilians, and has rejected accusations of war crimes.

Russia sent tens of thousands of troops into Ukraine on Feb 24 in what it called a special operation to degrade its southern neighbour's military capabilities and root out people it called dangerous nationalists.

Ukrainian forces have mounted stiff resistance and the West has imposed sweeping sanctions on Russia in an effort to force it to withdraw its forces.

Separately, a leading rights group said on Sunday it had documented "apparent war crimes" committed by Russian military forces against civilians in Ukraine.

Human Rights Watch issued a statement saying it had found "several cases of Russian military forces committing laws-of-war violations" in Russian-controlled regions such as Chernihiv, Kharkiv and Kyiv.

The statement, published in Warsaw, came one day after dead civilians were found lying scattered through the streets of the Ukrainian country town of Bucha near Kyiv, three days after the Russian army pulled back from a month-long occupation.

The New York-based Human Rights Watch referred to Bucha in its statement, for which it said it had interviewed 10 people including witnesses, victims and local residents, in person or by phone.

It said some had been too scared to give their full names.

"The cases we documented amount to unspeakable, deliberate cruelty and violence against Ukrainian civilians," said Mr Hugh Williamson, the group's Europe and Central Asia director.

"Rape, murder, and other violent acts against people in the Russian forces' custody should be investigated as war crimes."

These, it said, included one case of repeated rape; two cases of summary execution - one of six men - and other cases of unlawful violence and threats against civilians between Feb 27 and March 14.

"Soldiers were also implicated in looting civilian property, including food, clothing, and firewood. Those who carried out these abuses are responsible for war crimes," the report said.

Reuters was not immediately able to verify the Human Rights Watch evidence.

The group said that, on March 4, Russian forces in Bucha had "rounded up five men and summarily executed one of them".

Reuters journalists visited Bucha on Saturday and Sunday, after being given access by Ukrainian forces who recaptured the area, and saw bodies wearing no military uniforms scattered in the streets.

On Sunday, Bucha's mayor Anatoliy Fedoruk showed a Reuters team two corpses with white cloth tied around their arms, which the mayor said residents had been forced to wear during the month that Russian forces occupied the city.

Human Rights Watch said all parties to the armed conflict in Ukraine were obligated to abide by international law and the laws of war.

"Russia has an international legal obligation to impartially investigate alleged war crimes by its soldiers," Mr Williamson said.

Russia's defence ministry did not immediately respond to the specific allegations in the Human Rights Watch statement.