UN head António Guterres has condemned Russia's invasion of Ukraine as an "affront" to the world's collective conscience at a meeting of the General Assembly nearly one year on.

The meeting was debating a motion backed by Ukraine and its allies demanding Russia pull out immediately and unconditionally.

Ukraine hopes that by supporting the motion countries will show solidarity.

The Kremlin has accused the West of wanting to defeat Russia at any cost.

Vasily Nebenzya, the Kremlin's ambassador to the UN, said the US and its allies were prepared to plunge the entire world into war.

Russian President Vladimir Putin sent up to 200,000 soldiers into Ukraine on 24 February 2022 in the biggest European invasion since the end of World War Two.

The devastating war that ensued has left at least 7,199 civilians dead and thousands of others injured, according to a UN estimate, but that number is likely to be much higher.

The mayor of the Ukrainian city of Mariupol, where mass executions are alleged to have taken place, estimated in April that 21,000 people had died there alone.

Russia and Ukraine have each seen at least 100,000 of their soldiers killed or injured, according to the US military.

More than 13 million people were made refugees abroad or displaced inside Ukraine.

Mr Putin's claim that his operation was needed to "demilitarise and denazify" Ukraine, a country with historic ties to Russia, was dismissed by Ukraine and its allies as a ruse for an unprovoked attack.

"That invasion is an affront to our collective conscience," Mr Guterres told the General Assembly. "It is a violation of the United Nations Charter and international law."

The possible consequences of a "spiralling conflict" were, he said, a "clear and present danger".

Mr Guterres said the war was "fanning regional instability and fuelling global tensions and divisions, while diverting attention and resources from other crises and pressing global issues".

There had, he said, been "implicit threats to use nuclear weapons".

"It is high time to step back from the brink," he said.

"Complacency will only deepen the crisis, while further eroding our shared principles proclaimed in the Charter. War is not the solution. War is the problem. People in Ukraine are suffering enormously. Ukrainians, Russians and people far beyond need peace."

Sixty countries have sponsored the resolution, which stresses "the need to reach, as soon as possible, a comprehensive, just and lasting peace in Ukraine in line with the principles of the Charter of the United Nations."

The UN is likely to approve the resolution, which is not legally binding but carries political weight. However, it is unlikely that the vote will have much influence on Russia's actions in Ukraine.

Voting will take place later on Thursday, the eve of the invasion's first anniversary.

Over the past year, the General Assembly has voted on similar resolutions opposing Russia's invasion. In October 143 member states voted to condemn Moscow's illegal annexation of parts of Ukraine. Russia, Belarus, Syria, and North Korea opposed the motion, while India and China were among the 35 states that abstained.

Mr Guterres was speaking after Russia's President Vladimir Putin gave a speech blaming the West for the war.

In his address to the nation on Tuesday, Mr Putin also announced Russia's decision to suspend a key nuclear arms treaty after US President Joe Biden, fresh from a surprise visit to Kyiv, praised Western democracy for standing up to Russian aggression.

Mr Biden has called the decision to suspend the treaty, designed by the US and Russia in 2010 to prevent nuclear war, a big mistake.

On Wednesday, Mr Putin met China's top foreign policy official, Wang Yi, in Moscow and said co-operation with Beijing was "very important to stabilise the international situation". The visit marked an end to China's claim to neutrality regarding the war in Ukraine.