Ukrainian President Volodymyr Zelenskyy has harshly criticized Russia in an online speech during a meeting of the UN Security Council.

The meeting on Tuesday came as Ukrainian officials confirmed hundreds of civilian casualties near the capital Kyiv after Russian troops pulled out of the region.

Zelenskyy delivered a speech to the UN for the first time since the start of Russia's invasion.

He said, " Yesterday I returned from our city of Bucha, recently liberated from Russian troops, not far from Kyiv. So there is not a single crime that they would not commit there. The Russian military searched for and purposefully killed anyone who served our country. They shot and killed women outside their houses when they just tried to call someone who is alive. They killed entire families, adults and children and they tried to burn the bodies. I am addressing you on behalf of the people who honored the memory of the deceased every single day."

Russian leaders still deny being involved in the killings. Moscow claims the bodies were "stage managed" after Russian troops withdrew from the area.

Russian Foreign Minister Sergey Lavrov said, " Another fake news attack was undertaken in the town of Bucha, in the Kyiv region, after the Russian military had left in accordance with plans and agreements."

But a report from the New York Times analyzed videos and satellite imagery of the town. It appears to show the bodies lying on the streets while the Russians were still in control of the area.

Meanwhile, Russian forces have intensified air attacks in eastern and southern Ukraine. They claim they destroyed ammunition storage facilities.

The mayor of Mariupol called the situation in his city tragic. Residents have been facing a lack of water, food and electricity for over a month.

The mayor said more than 100,000 people remain trapped in the city. He accused Russian forces of obstructing evacuations.