Andriy Nebitov did not specify what each of the war crimes were nor how many people they involved.

However, he told Sky News in an interview on Tuesday that most of the deaths recorded so far had been caused by Russian shelling and rocket fire.

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"In other words, the cause of death is wounds from explosions and debris," he said.

"We also record facts of torture of people and actual execution with automatic weapons."

The top Kyiv police officer was speaking at the site of one of many potential war crime scenes in the town of Bucha, northwest of the capital.

A pile of bodies, burnt beyond recognition, lay cordoned off, behind police tape.

Yellow plaques, numbered one to six, were all that distinguished the remains of one life from another.

Investigators are still trying to work out what happened to the victims. Their identities - like so many unclaimed corpses in the town - are yet to be confirmed.

Initial inquiries appear to indicate that they had been shot dead and set alight by Russian soldiers.

The remains look to include women and a possible teenage child.

Mr Nebitov said investigators would first examine the bodies. Next, they would be put into black bags and taken to a morgue.

"There they are examined by forensic medical experts," he said.

"They give us an opinion on the cause of death. This is attached to the criminal case file, after which the security service will investigate."

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Asked whether Ukraine would be able to launch an international investigation into suspected Russian war crimes, the police chief said he hoped so.

"Then everything will depend on the international court. Based on the practice of international war crimes investigations of the 20th century, we now have an opportunity to record the evidence of the criminal activities of the Russian army in higher quality and in a more comprehensive way," he said.

In Bucha alone, the death toll is still growing as more bodies are found. The police chief predicted the final number would be "very many".

Russian forces surged into this town in the initial days of the war, seizing control until they pulled back, under fire from Ukrainian soldiers, late last week.

"There is no total number [of bodies] yet," the police chief said.

"We are working every day. I have to say that there are a lot of people. Especially in the wooded area. On the streets. And we haven't looked at houses and flats yet."

He said forensic experts had so far examined 200 bodies mainly from the Bucha region and the next-door town of Irpin.