RUSSIAN forces stepped up their attack on the battered city of Severodonetsk by striking a chemical plant which sent a huge cloud of smoke into the air. New footage made by a Ukrainian defender shows a spewing cloud of nitric acid as Russian forces pushed to take the strategic city Severodonetsk. East2WestResidents were told to stay inside due to the corrosiveness of the nitric acid[/caption] East2WestNitric acid is yellow or red in colour and can be fatal if inhaled[/caption] Ukrainian authorities have warned people to stay inside due to the risk posed by toxic fumes after the blast. Nitric acid, which is yellow or red, is corrosive and can cause severe burns, ulcerations, and scarring when in contact with skin. Its vapour can also cause pulmonary edema when inhaled – which can be fatal. Luhansk governor Serhiy Haidai said the dangerous chemical release was caused by a Russian airstrike on a chemicals plant. READ MORE ON UKRAINE WAR 'STOP THE WAR' Russian war criminals slam Putin and beg him to end 'failed' invasion MOTHER'S GRIEF My husband and baby were killed by a Russian bomb - I need justice Haidai said an aerial attack from a Russian warplane led to the chemical release, exposing residents to toxic fumes, in a city with a normal population of 106,000, though many have fled from the advance of Vladimir Putin’s forces. Meanwhile, Moscow claimed that Ukrainian forces hit a nitric acid tank, triggering an explosion and release of the orange fumes. 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 Russian Investigative Committee announced a criminal investigation into the nitric acid release. Read More on The Sun CUTTING COSTS The 9 most expensive appliances to run revealed - how to cut costs RENAMING MY BABY I’m renaming my 5-month-old child after her mom died, it’s a split opinion Ukrainian President Volodymyr Zelensky has replied by blasting Moscow’s airstrikes in the frontline city as “madness”. In his video address, he condemned the airstrikes in the city but added he was not surprised by Russia’s attack. “Given the presence of large-scale chemical production in Severodonetsk, the Russian army’s strikes there, including blind air bombing, are just madness,” he said. “But on the 97th day of such a war, it is no longer surprising that for the Russian military, for Russian commanders, for Russian soldiers, any madness is absolutely acceptable.” It comes as Putin demanded the city was captured by yesterday (Wednesday 30 May). Both sides said Russian forces now controlled between a third and half of the city – but Ukrainian forces are still resisting. Russia’s separatist proxies acknowledged that capturing the city was taking longer than hoped, despite one of the biggest ground assaults of the war. The National Health Service (NHS) recommends anyone who comes in contact with nitric acid seek immediate medical attention. Victims are encouraged to irrigate with water for at least 30 minutes after contact and should avoid rubbing their eyes or keeping their eyes closed. The skin should be flushed with copious amounts of water for at least 15 minutes and all contaminated clothing and shoes should be immediately removed. East2WestRussians now control 70 percent of Severodonetsk, in the Luhansk region of Ukraine[/caption] East2WestRussia has made the war in eastern Ukraine its priority[/caption] East2WestLuhansk governor Serhiy Haidai said the chemical release was caused by a Russian airstrike[/caption] East2WestNitric acid is a colorless fuming liquid with a suffocating odour[/caption] Most read in News 'STOP THE WAR' Russian war criminals slam Putin and beg him to end 'failed' invasion BAD SEED Sperm donor with genetic condition who fathered 15 kids says he 'did a GOOD thing' SUDDEN DEATH Qatari prince's ex found dead after claiming he 'touched' a child TUBE EMERGENCY Rush hour travel chaos as Tube station evacuated & cops hurry to scene 'OUTCAST' My child was made to eat Jubilee picnic on SEPARATE field to the other kids YOU'VE BEEN WARNED UK's most dangerous places to live for burglaries revealed