Russian forces have seized Chernobyl after intense gunfire at the site of the world's worst nuclear disaster.
Fighting between Ukrainian and Russian forces in the area in the north of the country may have led to damage at the facility, although these reports are yet to be independently verified.
Large parts of Chernobyl were closed to the public for decades after a nuclear power reactor melted down there during the Soviet Union's reign in 1986.
"Advisor to Ukrainian interior ministry says Russian forces entered Chernobyl and that fighting there destroyed a nuclear waste storage facility," NBC's Richard Engel tweeted this afternoon.
This was initially reported, but was later clarified due to a mistranslation.
He added shortly after: "Clarifying: advisor says heaving fighting MAY disturb nuclear waste."
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After a two-hour fight Russian forces were reported to be in control of the facility and have taken hostages.
An adviser for the Interior Minister of Ukraine, Anton Gerashchenko said today, according to LBC: "The invaders from the territory of Belarus have moved into the Chernobyl AES Zone.
"The National Guardsmen, who guard the collectors of unsafe nuclear radioactive waste, are fighting hard.
"If the invaders artillery hits and ruins/damages the collectors of nuclear waste , radioactive nuclear dust can can be spread over the territory of Ukraine, Belarus and the country of the EU!"
The President of Ukraine took to Twitter to say Russian forces are trying to seize the zone.
"Russian occupation forces are trying to seize the #Chornobyl_NPP," tweeted Volodymyr Zelenskyy.
"Our defenders are giving their lives so that the tragedy of 1986 will not be repeated. Reported this to @SwedishPM.
"This is a declaration of war against the whole of Europe."
It comes after President Vladimir Putin said allies of Ukraine who try to interfere with his attack will "face consequences greater than any you have faced in history", in what was a chilling warning.
Air sirens have been heard across the city centre, reports the Mirror's Andy Lines from Kyiv, as residents try to flee for safety.
Five Ukrainians have also lost their lives after a military plane was shot down.
Photos also showed a radar station that Russia had bombed on outskirts on Mariupol.
Terrifying footage also showed a number of Russian helicopters swarming towards the Ukrainian capital as they fired missiles at an airport.
Western officials believe Russia intends to seize and control a very large section of Ukraine - including the capital Kiev - and will need ground troops to do so.
They fear this will lead to large numbers of civilian injuries and deaths with fighting in the built-up urban area but are yet unclear whether that will mean occupying the whole country, for which Russian forces don't yet appear to be ready.
The United Nations refugee agency said on Thursday that the situation in Ukraine was quickly deteriorating after Russia's invasion and pleaded with neighbouring countries to keep their borders open to people seeking protection.
Poland is one country currently preparing hospitals to help Ukrainians who have been injured in the conflict.
The nation had prepared a list of 120 hospitals where Ukrainians could be treated.
Ukrainian Ambassador to the UK Vadym Prystaiko said Ukraine is "putting up a real fight" but added some places are proving difficult to defend.
"We are defending our land," he said.
Earlier, Boris Johnson condemned Russia for unleashing a "tidal wave of violence" against Ukraine without provocation or credible excuse.
"It is an attack on democracy and freedom in East Europe and around the world," he said in a statement before addressing the country again this evening.
"This crisis is about the right of a free, sovereign independent European people to choose their own future and that is a right that the UK will always defend."
