Europe's biggest nuclear power plant has been shelled by Russian forces in Ukraine, with a fire breaking out.
The attack on the northeastern city on Energodar and its Zaporizhzhia nuclear plant unfolded as the invasion entered its second week.
Local politicians initially said firefighters were unable to get close to the scene because they were being shot at - but a team of 40 people and 10 units have now extinguished the blaze.
Ukrainian officials have said there is a "real threat of nuclear danger", with Foreign Minister Dmytro Kuleba warning: "If it blows up, it will be 10 times larger than Chernobyl."
Russian army is firing from all sides upon Zaporizhzhia NPP, the largest nuclear power plant in Europe. Fire has already broke out. If it blows up, it will be 10 times larger than Chornobyl! Russians must IMMEDIATELY cease the fire, allow firefighters, establish a security zone!
— Dmytro Kuleba (@DmytroKuleba) March 4, 2022
The International Atomic Energy Agency (IAEA) has said that the fire has not affected essential equipment or caused radiation levels to change.
US officials have also stressed that reactors at Zaporizhzhia power station are protected by robust containment measures, and are now being safely shut down.
A video, posted by Ukraine's President Volodymyr Zelenskyy, appears to show large explosions at the power station.
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Zelenskyy calls for action
President Zelenskyy also gave an emotional speech overnight, in which he warned an explosion at the nuclear power plant could spark "the evacuation of Europe".
Mr Zelenskyy added: "Only urgent action by Europe can stop the Russian troops. Do not allow the death of Europe from a catastrophe at a nuclear power station."
Energy experts have said there is nothing to indicate an impending disaster, with the American Nuclear Society saying: "The real threat to Ukrainian lives continues to be the violent invasion and bombing of their country."
Jon B Wolfsthal, a former special adviser to Joe Biden when he was US vice-president, added: "Everyone needs to take a step back and not jump to conclusions."
Nonetheless, the assault triggered late-night phone calls between Mr Zelenskyy and Western leaders - with the US Energy Department activating its nuclear response team as a precaution.
File photo of Zaporizhye - Europe’s largest nuclear power plant - in Energodar, Ukraine. Picture by: EnergoatomUkraine's president also spoke to his American counterpart early on Friday morning - with Joe Biden receiving a separate update from the US Energy Department's under-secretary for nuclear security.
On Thursday, footage from Energodar showed flames and black smoke rising above the city, which had a population of 50,000 before the war began.
Energoatom, the company that operates Ukraine's nuclear power plants, had warned: "Many young men in athletic clothes and armed with Kalashnikovs have come into the city. They are breaking down doors and trying to get into the apartments of local residents."
Ukraine's Prime Minister Denys Shmyhal has called on the West to close the skies over the country's nuclear plants as fighting intensifies - warning in a statement that "the security of the whole world is at stake".
But the US and NATO allies have ruled out establishing a no-fly zone because such a move would pit Russian and Western military forces against each other.
Russia has already captured the defunct Chernobyl plant - the site of the 1986 accident that is considered to be the worst nuclear disaster in history.
'Worst is yet to come'
On Thursday Ukraine said it had come to a 'joint understanding' with Russia to allow the evacuation of civilians as the invasion continues.
Following the latest round of talks, both sides said they supported the opening of humanitarian corridors.
Russia also left the door open to a possible ceasefire.
While the French President Emanuel Macron warned that the "worst is yet to come" after holding a 90-minute call with Russian President Vladimir Putin.
Mr Putin used the call to claim his war was going to plan - and warned that Moscow aims to take full control of Ukraine by diplomatic or military means.
A spokesperson for President Macron said he told the Russian president he was making a "major mistake" and that he was "lying to himself" about how the invasion was progressing.
The official said the French president warned his Russian counterpart that his actions would leave Russia "isolated, weakened and under sanctions for a very long time".
Reporting by: IRN
