Ukrainian President Volodymyr Zelenskiy told the United Nations Security Council on Tuesday that “accountability must be inevitable” for Russia as he accused invading Russian troops of committing “the most terrible war crimes” since World War Two.

Zelenskiy showed a short video of burned, bloodied and mutilated bodies, including children, in Irpin, Dymerka, Mariupol and Bucha, where Ukraine accuses Russian troops of killing hundreds of civilians.

Russia’s UN Ambassador Vassily Nebenzia then told the Security Council that Russian troops are not targeting civilians, dismissing accusations of abuse as lies. He said that while Bucha was under Russian control “not a single civilian suffered from any kind of violence.”

Zelenskiy questioned the value of the 15-member UN Security Council, which has been unable to take any action over Russia’s February 24 invasion of Ukraine because Moscow is a veto power, along with fellow permanent council members the United States, France, Britain and China.

“We are dealing with a state that turns its veto at the UN Security Council into the right to (cause) death,” Zelenskiy said in a live video address from Ukraine’s capital Kyiv, urging reform of the world body. “Russia wants to turn Ukraine into silent slaves.”

Russia says it is carrying out a “special military operation” that aims to destroy Ukraine’s military infrastructure and “denazify” it, and denies attacking civilians. Ukraine, a parliamentary democracy, and Western countries say Moscow invaded without provocation.

Russia’s partner China, which has abstained on most UN votes since the war started, was “deeply disturbed” by the images of civilian deaths in Bucha, China’s UN Ambassador Zhang Jun said, calling for verification of what happened.

India, which relies heavily on Russia for military hardware and has also abstained on UN action, condemned the killings in Bucha and called for an independent investigation.

Russia’s Nebenzia said: “We are not shooting against the civilian targets in order to save as many as civilians possible. This is precisely why we’re not advancing as fast as many expected.”

‘Show backbone’

The US ambassador to the United Nations, Linda Thomas-Greenfield, said responsible world powers and global leaders need to “show backbone - and stand up to Russia’s dangerous and unprovoked threat against Ukraine and the world.”

“No one can be a shield for Russia’s aggression,” she said as Washington pushes to suspend Russia from the Geneva-based UN Human Rights Council.

The 193-member UN General Assembly in New York is likely to vote on the move to suspend Russia on Thursday, diplomats said. A two-thirds majority of present voting members is needed.

Nebenzia responded: “I hope that our colleagues from the United Nations will not allow themselves to be manipulated and play up to Washington.”

The United Nations said some 11 million Ukrainians — more than a quarter of the population — have fled their homes. More than 4 million of those people have left Ukraine.

UN aid chief Martin Griffiths said at least 1,430 civilians have been killed, including more than 121 children. “We know this is likely a serious underestimate,” he added.

Griffiths, who is seeking a humanitarian truce in Ukraine, said “we have a long road ahead of us” after what he described as a “frank” meeting with Russia’s Foreign Minister Sergei Lavrov in Moscow on Monday. Griffiths said he hopes to travel to Ukraine on Wednesday to meet with Ukrainian officials.

UN political affairs chief Rosemary DiCarlo said UN human rights monitors were seeking to verify allegations of sexual violence by Russian forces.

“These include gang rape and rapes in front of children,” she said. “There are also claims of sexual violence by Ukrainian forces and civil defense militias.”

UN Secretary-General Antonio Guterres warned the Security Council that Russia’s invasion of Ukraine is one of the greatest challenges ever to the international order “because of its nature, intensity, and consequences.”