Civilians were fleeing parts of eastern Ukraine on Tuesday in the wake of an impending Russian attack, while Kyiv said it was investigating reports that Russian forces had used chemical weapons in the besieged port city of Mariupol. The battle for Mariupol, where the regional governor said tens of thousands may have been killed, seemed to have reached a decisive stage, with Ukrainian Marines stationed in the Azovstal industrial area. If the Russians occupy Azovstal, they would have full control of Mariupol, the beacon between Russian-controlled areas to the west and east. The city has already been devastated by weeks of Russian bombing. Deputy Defense Minister Hanna Malyar said the government was checking unverified information that Russia may have used chemical weapons while besieging Mariupol. “There is a theory that these could be phosphorus munitions,” Malyar said in a televised comment. President Volodymyr Zelensky had said Monday night that Russia could resort to chemical weapons as it rallied troops in the eastern Donbass region for a new offensive in Mariupol. He did not say if they were actually used. The United States and Britain have said they are trying to verify the reports. The governor of the eastern Donetsk region, Pavlo Kirilenko, said he had seen reports of possible use of chemical weapons in Mariupol, but could not confirm them. “We know that last night around midnight a drone dropped a hitherto unknown explosive device and the people in and around the metal factory in Mariupol, three people, began to feel unwell,” he told CNN. They were taken to hospital and their lives were not in danger, he said. Asked about the total number of dead in Mariupol, Kyrylenko said: “We are currently talking about 20-22,000 dead”, adding that the number should be checked very carefully. The production, use and storage of chemical weapons is prohibited under the 1997 Chemical Weapons Convention (CWC). Although condemned by human rights groups, white phosphorus is not banned under the CWC. Russia’s Defense Ministry did not respond to a request for comment. Russian-backed separatist forces in the east have denied using chemical weapons in Mariupol, the Interfax news agency reported. MURAT YUKSELIR / THE GLOBE AND MAIL, SOURCE: GRAPHIC NEWS But if it proves to be so, it would mean a dangerous new development in a war that has already left its mark on Russia since Russian President Vladimir Putin sent his troops across the border on February 24. About a quarter of Ukraine’s 44 million people have been forced to flee their homes, cities have been reduced to rubble and thousands have been killed or injured – many of them civilians. Putin has called the move a “special military operation” to demilitarize and “demilitarize” Ukraine, but has sparked condemnation and alarm in the West, which has imposed a wide range of sanctions to stifle the Russian economy. After their troops marched in front of the Ukrainian resistance, the Russians for the time being abandoned their attempt to occupy the capital Kyiv. They are doubling their efforts in the east and Ukrainian forces are digging to face a new attack. The governor of Luhansk region, Serhiy Gaidai, urged residents to evacuate using five humanitarian corridors agreed for the east. “It is much scarier to stay and burn in your sleep than a Russian shell,” he wrote on social media. “Evacuation, with each passing day the situation is getting worse. Take the essentials and head to the pick-up point. “ In all, nine humanitarian corridors were agreed for Tuesday, including one from Mariupol, Deputy Prime Minister Iryna Vereshchuk said. The General Staff of the Armed Forces of Ukraine said that in addition to trying to take control of Mariupol, Russian forces intended to occupy Popasna, a town about two hours drive west of Luhansk, and were to launch an attack in the direction of Kura. in Donetsk. . Ukrainian troops repulsed attacks in both Luhansk and Donetsk, he said. President Zelensky overnight called for more weapons from the West to help end the siege of Mariupol and repel the impending eastern offensive. “Unfortunately we are not getting as much as we need to end this war faster; in particular, to lift the blockade of Mariupol,” he said. Separately, in a speech to the Lithuanian parliament, Zelensky urged the European Union to impose sanctions on all Russian banks and Russian oil and to set a deadline for ending Russian gas imports. “We can not wait,” he said. The withdrawal of Russian forces from the outskirts of Kiev has brought to light allegations of war crimes, including the execution and rape of civilians. Moscow rejects them and in turn has accused the Ukrainian forces of sexual violence. “We hear more and more about rape and sexual violence,” UN official Sima Bachus told the Security Council on Monday. “Violence and rape are now being used as weapons of war by Russian invaders in Ukraine,” Kateryna Cherepakha, president of the human rights group La Strada-Ukraine, told the council via video. Russia’s deputy ambassador to the UN has denied the allegations. The Russian Defense Ministry said the Ukrainian government was being led by the United States to sow false evidence of Russian violence against civilians despite what it called “Moscow’s unprecedented measures to rescue civilians.” Putin said on Tuesday that Moscow’s military operation would undoubtedly achieve its “noble” goals. Speaking at a ceremony at the Vostochny Cosmodrome in Russia’s Far East, Putin was quoted as saying by Russian news agencies that Moscow had no choice but to act to protect Russia and that a confrontation with Ukrainian anti-Russian forces was imminent. He is scheduled to meet with Belarussian President Alexander Lukashenko to discuss Ukraine and Western sanctions. Belarus is a region for Russian forces. Drone footage shot on April 10 at the Mariupol Drama Theater shows the extent of the damage to the building that was damaged during the fierce fighting for the city. Reuters The Morning and Afternoon newsletters are compiled by the Globe editors, giving you a brief overview of the day’s most important headlines. Register today.