Sharjah24 – AFP: Russian troops attacked Europe's largest nuclear power plant on Friday, setting part of the Ukrainian facility ablaze in an assault the country's leader branded "nuclear terror" and said could endanger the continent.

Local authorities said no immediate radiation rise was detected and "essential" equipment was unaffected by the fire, but it remained unclear what the invading forces planned next.

President Volodymr Zelensky spoke with world leaders, including US President Joe Biden and British Prime Minister Boris Johnson, who called for a halt to fighting at the Zaporizhzhia nuclear plant.

Images on a live feed from the Zaporizhzhia nuclear plant site earlier showed blasts lighting up the night sky and sending up plumes of smoke.

Zelensky angrily denounced the attack, in a video message saying: "No country other than Russia has ever fired on nuclear power units."

"This is the first time in our history. In the history of mankind. The terrorist state now resorted to nuclear terror," he added, calling for global help.

"If there is an explosion, it is the end of everything. The end of Europe. This is the evacuation of Europe. Only immediate European action can stop Russian troops."

Despite the fears, after several hours of uncertainty, Ukrainian authorities said the site had been secured.

"The director of the plant said that the nuclear safety is now guaranteed," Oleksandr Starukh, head of the military administration of the Zaporizhzhia region, said on Facebook.

"According to those responsible for the plant, a training building and a laboratory were affected by the fire," he added.

And the IAEA said it had been told by Ukraine's regulator that "there has been no change reported in radiation levels" at the site.

"Ukraine tells IAEA that fire at site of Zaporizhzhia Nuclear Power Plant has not affected 'essential' equipment, plant personnel taking mitigatory actions," the watchdog added in a tweet.

US Energy Secretary Jennifer Granholm also tweeted that "the plant's reactors are protected by robust containment structures and reactors are being safely shut down".