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Russian artillery fire struck Ukraine's largest nuclear plant, sparking a fire hours after international atomic regulators warned that combat at the facility could wreak havoc, according to Ukraine authorities.

The International Atomic Energy Agency said it was aware of the incident and in contact with Ukrainian authorities. The agency said Ukrainian regulators reported that radiation levels appeared normal despite the shelling and that "essential" equipment had not been damaged. Crews were working to "mitigate" the damage.

The U.S. Department of Energy also said it was monitoring the situation and had not detected elevated readings.

President Volodymy Zelenskyy released a video after speaking with President Biden and other world leaders, calling on Europeans to "wake up."

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"The biggest nuclear power plant in Europe is on fire right now," he said, according to a translation of his remarks. "Russian tanks are shooting at the nuclear blocks. These are tanks equipped with thermal imagers, so they know what they are shooting at."

He noted that the Zaporizhzhya plant has six reactors. Only one exploded at Chernobyl - devastating the region in 1986.

"For the first time ever in our history, in the history of humankind, the terrorist country has reverted to nuclear terror," Zelenskyy added. "Russian propaganda had warned in the past to cover the world in nuclear ash. Now this isn’t just a warning, this is real."

"Do not let Europe die in the nuclear catastrophe," he said.

The facility has an automated radiation monitoring system on its website. Experts told Fox News Digital that the data appeared normal after reports of the fire and that a meltdown was unlikely unless the bombardment caused overheating.

Video posted to Telegram, an encrypted messaging app, early Friday local time appeared to show a projectile landing outside the facility, creating a large fireball.

Dmytro Kuleba, Ukraine's Minister of Foreign Affairs, tweeted that Russian forces were "firing from all sides" on the facility.

"Fire has already broken out," he wrote – a claim that appears to be supported by grainy livestream video. "If it blows up, it will be 10 times larger than Chernobyl."

Earlier Thursday, the IAEA warned of a potential for catastrophe as Russian forces were closing in on Zaporizhzhya, the largest nuclear power plant in Europe.

"We demand that they stop the heavy weapons fire," Andriy Tuz, spokesperson for the plant in Enerhodar, said in another video posted on Telegram earlier. "There is a real threat of nuclear danger in the biggest atomic energy station in Europe."

Ukraine’s deputy interior minister had also raised concerns that violence there could result in a massive radioactive disaster.

"Because of [Vladimir] Putin’s madness, Europe is again on the brink of a nuclear disaster," Anton Herashchenko wrote in a translated Facebook post. 

He shared images showing makeshift defenses in Enerhodar, the city where the Zaporizhzhya power plant is located. The Ukrainian government began warning Wednesday that Russian activity in the area could result in a new "nuclear catastrophe."

"Russians are trying to enter Enerhodar," Ukrainian Member of Parliament Andrii Osadchuk confirmed to Fox News Digital. 

Rafael Grossi, the director of the International Atomic Energy Agency, issued a statement Thursday calling on both sides to avoid violence near Zaporizhzhya after reports that Russian infantry had taken the surrounding area.

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Separately, the IAEA said Ukraine had reported "psychological pressure and moral exhaustion" among workers at the Chernobyl site, which Russian forces seized early in the invasion last week. 

Herashchenko warned that the volatile situation could lead to another crisis like in Chernobyl in 1986, or at Japan’s Fukushima power plant after a tsunami in 2011.

Nuclear barricade

Ukraine's Deputy Minister of Interior Anton Herashchenko shared this image of a makeshift blockade across the road leading to the nuclear plant. (Anton Herashchenko)

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"Radiation knows no nationalities," he said. "It kills indiscriminately."

Hundreds of members of Ukraine’s Parliament, known as the Verkhovna Rada, who have remained in Kyiv met Thursday. They discussed and voted on a number of issues, including asking the United Nations and European Parliament to establish a no-fly zone over Ukraine – in part to protect the country’s nuclear plants and other combustible infrastructure.

Ukraine has 15 operational nuclear reactors at four separate sites, according to the IAEA. Six of the reactors are in Zaporizhzhya.

Osadchuk said lawmakers also agreed to strict new national security measures and a law to nationalize Russian property.

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In a statement, the Rada said it adopted 14 new laws and a resolution.

Ukrainian officials have accused Russian forces of increasingly targeting civilians and infrastructure, which the Kremlin denies.

Videos show widespread destruction in and around Kharkiv, Ukraine's second-largest city, as well as the besieged capital Kyiv.

On Thursday, a Russian airstrike took out a purported ammo depot in the city, sending dark plumes of smoke skyward. Earlier this week, a separate strike leveled a civilian TV tower near the Babyn Yar Holocaust memorial site, killing at least five people.

Defense forces said their anti-air weapons took down a Russian rocket near the city's central train station, which damaged the building but claimed no lives.

The fighting at Enerhodar, near the Dnieper River, comes as Russian forces have seized the waterfront city of Kherson and were battling Ukrainian defenders in another port city, Mariupol.

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Along with Russia's 2014 seizure of Crimea, conquering Ukraine's southern ports would cut the country off from shipping lanes and give Putin's forces greater logistical control of the area.

Ukrainian and Russian envoys met earlier Thursday for talks in neighboring Belarus to discuss ways to evacuate civilians.

The Associated Press contributed to this report.