This is the moment a cloud of poisonous nitric acid spews orange fumes into the sky after a Russian airstrike on a chemical plant.
Luhansk governor Serhiy Haidai said the explosion was caused by a Russian airstrike while the Kremlin said it was Ukrainian forces that hit the nitric acid tank,
The footage was captured by a Ukrainian soldier.
A Russian source said: “Footage has emerged of an explosion of a chemical tanker, presumably containing nitric acid, set off by the Ukrainian armed forces at the Azot plant in Severodonetsk.
“The relaxed behaviour of Ukrainian soldiers confirms that Russian artillery was not shelling the plant at the time of the explosion.”
The Russian Investigative Committee announced a criminal investigation into the nitric acid release.
Mr Haidai said an aerial attack from a Russian warplane led to the chemical release.
He said thousands of residents were exposed to toxic fumes.
It is unclear how many residents of the city's 106,000 population are still there as many have fled since the start of the invasion in February.
Haidai told the BBC : "Our troops still remain in the city and for the time being are still resisting the Russian army.
"But if they need to withdraw to the other side of the river, closer to Lysychansk, in order to preserve troops then they will probably do so.”
It comes one day after a Kremlin TV propagandist has claimed World War 3 has already begun and claims Russia ’s task is now to “demilitarise” NATO.
Rossiya-1 anchor Olga Skabeyeva is seen on a video claiming that the much-vaunted Russian special military operation in Ukraine “is now over”.
The West’s provision of arms to Ukraine meant it was now a global conflict, she said, as Russia's enemy showcased new British Wolfhound heavy tactical support vehicles.
“It's time to admit, perhaps, that Russia's special operation in Ukraine is now over,” said Skabeyeva.
“In the sense that a real war has started, World War 3. We are being forced to demilitarise, not just Ukraine but NATO as a whole.
"Why am I talking about this? It was not only Smerch MLRS with cluster munitions that struck Donetsk.
“The strikes were carried out with… American M777 howitzers.”
