Volodymyr Zelenskiy taking chemical weapons threat ‘seriously’ as Mariupol mayor says thousands have died in devastated port city

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Ukrainian president Volodymyr Zelenskiy has voiced concerns that Russian forces are preparing “a new stage of terror” that could involve the use of chemical weapons in Ukraine, as the mayor of Mariupol said that more than 10,000 civilians had died so far in the Russian siege of his city.

“Today, the occupiers issued a new statement, which testifies to their preparation for a new stage of terror against Ukraine and our defenders,” Zelesnkiy said early on Tuesday. “One of the mouthpieces of the occupiers stated that they could use chemical weapons against the defenders of Mariupol. We take this as seriously as possible.”

US officials pointed to new signs that Russia’s military is gearing up for a major offensive in Ukraine’s eastern Donbas, switching its focus after failing in their initial drive to capture Kyiv. A senior US defence official described a long convoy now rolling toward the eastern city of Izyum with artillery, aviation and infantry support, as part of redeployment to the east.

Ukrainian authorities are warning people not to go near what they say are landmines being dropped on Kharkiv. Zelenskiy also spoke of “hundreds of thousands of dangerous objects” including mines and unexploded shells left by Russian forces in regions in Ukraine’s north.

Austria’s chancellor, Karl Nehammer, has said he told Putin during frosty talks that “all those responsible” for war crimes must be brought to justice and warned that western sanctions would intensify as long as people kept dying in Ukraine.

Sweden’s ruling party has begun debating whether the country should join Nato, and neighbouring Finland expects to reach a decision within weeks, as Moscow warned that the Nordic nations’ accession would “not bring stability” to Europe.