WASHINGTON (REUTERS) - Ukrainian President Volodymyr Zelenskiy said on Wednesday (April 13) in an address to Estonia’s parliament that Russia was using phosphorous bombs in Ukraine, accusing Moscow of using terror tactics against civilians.  

He did not provide evidence and Reuters has not been able to independently verify his claim.  

Mr Zelensky added that instruments needed to be found to pressure Russia to stop forcibly deporting Ukrainians and called for sanctions on Russia to continue, saying they were the only way to force Russia to agree to peace.

Russia said earlier on Wednesday that claims by the United States and Ukraine that Russia could use chemical weapons in Ukraine were disinformation because Moscow destroyed its last chemical stockpiles in 2017.

Ukraine's defence ministry said on Tuesday that it was checking claims that Russia may have used chemical weapons in the southern Ukrainian port city of Mariupol.

US Department of State Spokesman Ned Price told reporters on Tuesday that the United States was concerned Russia may seek to resort to chemical weapons in Ukraine.

Russia's embassy in Washington said Ukrainian radicals were preparing to stage provocations with the use of chemical weapons and that the State Department's Price was spreading disinformation.

"We call on Washington to stop spreading disinformation," the embassy said in a statement. "Ned Price once again distinguished himself by his idle talk, not substantiated by a single piece of evidence."

Ukraine’s Deputy Defence Minister Hanna Malyar said on Wednesday there was a high risk of Russia using chemical weapons against her country, echoing warnings by President Zelensky earlier in the week.

On Tuesday, Ms Malyar said authorities were checking unverified reports that Russia may have already used chemical weapons while besieging Mariupol and that there was a theory that phosphorous munitions had been used.

Russia sent tens of thousands of troops into Ukraine on Feb 24 in what it called a special operation to degrade its southern neighbour's military capabilities and root out people it called dangerous nationalists.

Ukrainian forces have mounted stiff resistance and the West has imposed sweeping sanctions on Russia in an effort to force it to withdraw its forces.

Russia says the West is gripped by discriminatory anti-Russian paranoia and says Western media have provided an excessively partial narrative of the war in Ukraine that largely ignores Russia's concerns about the enlargement of Nato and the persecution of Russian speakers.