Ukrainian President Volodymyr Zelenskyy lashed NATO for ruling out a no-fly zone over his country saying the Western military alliance knew further Russian aggression was likely.
On Friday local time, NATO rejected Ukraine's request to impose a no-fly zone to halt Russia's bombing, but Western allies did warn President Vladimir Putin of fresh sanctions if he does not stop the war.
"Knowing that new strikes and casualties are inevitable, NATO deliberately decided not to close the sky over Ukraine," Mr Zelenskyy said in a video published by the presidency.
"We believe that the NATO countries themselves have created a narrative that the closing of the skies over Ukraine would provoke direct Russian aggression against NATO."
NATO chief Jens Stoltenberg had said the alliance would not intervene in the conflict over fears of a direct clash with Moscow that could spiral into a wider conflict.
"The only way to implement a no-fly zone is to send NATO fighter planes into Ukraine's airspace, and then impose that no-fly zone by shooting down Russian planes," Mr Stoltenberg said after the urgent meeting.
"If we did that, we'll end up with something that could end in a full-fledged war in Europe, involving many more countries and causing much more human suffering."
But Mr Zelenskyy insisted that the NATO gathering was a "weak summit, a confused summit".
"All the people who die starting today will also die because of you. Because of your weakness, because of your disconnection," he said.
"Today the leadership of the alliance gave the green light for further bombing of Ukrainian cities and villages, refusing to make a no-fly zone."
'The world narrowly averted a nuclear catastrophe'
The United States and its allies heavily criticised Russia on Friday local time at the United Nations over its shelling and seizure overnight in Ukraine of Europe's biggest nuclear power plant, and some demanded that Moscow not let such an attack happen again.
Many of the Security Council's 15 envoys expressed "grave concern" and shock, warning against the possibility of a repeat of the 1986 Chernobyl disaster - a nuclear accident in Ukraine when it was part of then Soviet Union considered to be the worst in history.
They said the attack was against international humanitarian law and urged Moscow to refrain from any military operations targeting the nuclear facilities and allow Ukrainian personnel to be allowed onto the plant to carry out their work.
"The world narrowly averted a nuclear catastrophe last night," Linda Thomas-Greenfield, US Ambassador to the United Nations, told an emergency meeting of the Security Council, convened following the seizure of the Zaporizhzhia nuclear power plant in southeastern Ukraine by Russian troops.
"Russia’s attack last night put Europe’s largest nuclear power plant at grave risk. It was incredibly reckless and dangerous. And it threatened the safety of civilians across Russia, Ukraine and Europe," Ms Thomas-Greenfield said.
She urged Russian leader Vladimir Putin to end the invasion of Ukraine.
"Not only has he not listened, we've just witnessed a dangerous new escalation that represents a dire threat to all of Europe and the world," she said.
"President Putin must stop this humanitarian catastrophe by ending this war and ceasing these unconscionable attacks against the people of Ukraine," she said. "Mr Putin must stop this madness, and stop it now."
'It is a war crime to attack a nuclear power plant'
The US embassy in Ukraine labelled the attack against the power plant a possible war crime.
"It is a war crime to attack a nuclear power plant," the embassy tweeted.
Asked by news agency AFP whether Washington was openly accusing Moscow of having perpetrated a war crime prohibited by the Geneva Convention, the US State Department was more cautious.
"The intentional targeting of civilians or civilian objects, including nuclear power plants, is a war crime, and we are assessing the circumstances of this operation," a US State Department spokesman said.
"But regardless of the legality, this action was the height of irresponsibility, and the Kremlin must cease operations around nuclear infrastructure," the official said.
Russia's ambassador to the United Nations denied accusations that Russian forces had shelled Europe's largest atomic power plant in Zaporizhzhia.
"These statements are simply untrue," Vassily Nebenzia told the Security Council.
"This is all part of an unprecedented campaign of lies and disinformation against Russia."
Ukrainian army soldiers talk together on 4 March, 2022, in Irpin, Ukraine. Source: Getty / Europa Press News
He said the fighting occurred at a training complex "located just outside the territory of the nuclear power plant" and accused "Ukrainian saboteurs" of setting fire to the training facility.
"The operation of the nuclear power plant continues normally," Mr Nebenzia said.
"Nothing threatens the safety of the six power units.
"There is no threat of a release of radioactive material."
Lack of real-time monitoring of radiation levels concerning, experts say
International Atomic Energy Agency chief Raphael Grossi said the plant was undamaged.
Only one of its six reactors was working, at around 60 per cent of capacity.
The radiation monitoring system at the site was functioning normally and there had been no release of radioactive material, Mr Grossi said.
Russia's defence ministry said its forces were in control at the plant.
Park Jong-woon, a professor at the energy and electric engineering department of Dongguk University, said he did not think there was an immediate radiological threat posed by the plant's seizure, but added Russia could disrupt public access to radiation data to sow confusion.
"They can make people wonder, freak them out and spread fear," said Mr Park, who worked at state-run power operators between 1996 and 2009, helping build nuclear reactors.
Clashes around the Zaporizhzhia nuclear power plant after a fire broke out. Source: Anadolu / Zaporizhzhia Nuclear Power Plant/Anadolu Agency/Getty Images
"For example, the prospect of a widespread fire, although that appears not to be the case, could disable the plant's electrical systems and lead to an event very much like Fukushima if cooling is not restored in time," he said.
More broadly, experts expressed worries about access to real-time data necessary for gauging the radiation situation on the ground.
The official website for radiation readings at the Zaporizhzhia site was not immediately accessible as of Friday afternoon, Mr Lyman said.
Since last week's takeover by Russian forces of Chernobyl - the site of the world's worst nuclear disaster and now a defunct power plant - monitoring of radiation levels there has been more difficult, according to Kenji Nanba, who heads Fukushima University's Institute of Environmental Radioactivity and has been involved in a joint research project with Ukrainian scientists.
He said an official Ukrainian website with hourly radiation measurements from Chernobyl's exclusion zone had been down for days and that another site had gradually lost most of its real-time readings.
Russia intensifies crackdown on media outlets, blocks Facebook
Russia on Friday blocked Facebook and Twitter, while also moving to impose harsh jail terms for publishing "fake news" about the army as part of efforts to muffle dissent over Russia's invasion of Ukraine.
Social media staple Facebook was blocked over several instances of "discrimination" of Russian state media, according to media regulator Roskomnadzor.
"Soon millions of ordinary Russians will find themselves cut off from reliable information... and silenced from speaking," said Nick Clegg, president of global affairs at Facebook's parent Meta.
The news came as Russian President Vladimir Putin signed into law a bill introducing jail terms of up to 15 years for publishing "fake news" about the Russian army.
Russia's lower house said in a statement that if fake news stories "led to serious consequences, (the legislation) threatens imprisonment of up to 15 years".
Amendments were also passed to fine or jail people calling for sanctions against Russia.
The BBC, which has a large bureau in Moscow and runs a Russian-language news website, reacted by announcing a halt of its operations in Russia.
"This legislation appears to criminalise the process of independent journalism," BBC Director-General Tim Davie said in a statement.
He warned that journalists could face "the risk of criminal prosecution simply for doing their jobs".
Earlier this week the BBC said it was bringing back shortwave radio transmission to Ukraine and parts of Russia so people can listen to its programs with basic equipment.
Two Russian outlets, Nobel Prize-winning newspaper Novaya Gazeta and business news website The Bell, said Friday they will stop reporting on Russia's invasion of Ukraine to protect their journalists.
The past year has seen an unprecedented crackdown on independent and critical voices in Russia that has intensified since the invasion.
Russia's media watchdog said Friday it had restricted access to the BBC and other independent media websites, further tightening controls over the internet.
With additional reporting by Reuters.
