Jacinda Ardern defends New Zealand's aid to Ukraine, saying country is contributing to war effort. Video / Mark Mitchell
The World Health Organisation is preparing for "chemical assaults" in Ukraine, its European head said.
There has been no evidence of chemical weapons being used in Ukraine yet, however recent allegations of war crimes by Russia have left some fearing Putin could be prepared to unleash barbaric weapons upon civilians.
"Given the uncertainties of the current situation, there are no assurances that the war will not get worse," Hans Kluge, WHO regional director for Europe, said during a briefing from Lviv, Ukraine, Reuters reported.
UN humanitarian chief Martin Griffiths (5th R) reacts at the site of a mass grave in Bucha. Photo / Getty Images
"WHO is considering all scenarios and making contingencies for different situations that could afflict the people of Ukraine, from the continued treatment of mass casualties to chemical assaults."
Western officials have claimed Russia may use chemical weapons against civilians in Ukraine, but there is no evidence to suggest it has at this stage.
Moscow claims Kyiv could use chemical weapons against its own people before pointing the finger at Russia.
Russian troops have been accused of committing war crimes in recent days after massacres were found to have taken place in the Kyiv suburb of Bucha.
Ukraine's President Volodymr Zelenskyy accused Russian troops of killing civilians in Bucha "for pleasure" in an emotional speech before the UN Security Council earlier this week.
Describing alleged atrocities, Zelenskyy said people "were killed in their apartments, houses... civilians were crushed by tanks while sitting in their cars in the middle of the road, just for their pleasure".
He told the Council, including Moscow's envoy, that women were raped in front of their children, and that civilians had their throats slashed, limbs cut off and tongues cut out.
Accusing Russia of genocide, Zelenskyy said: "They killed entire families, adults and children, and they tried to burn the bodies."
Zelenskyy compared Russia to ISIS and accused Putin of "exporting" his hatred into other countries, not only Ukraine.
A man pushes his bike through debris and destroyed Russian military vehicles on a street in Bucha. Photo / Getty Images
Zelenskyy added that "hundreds of thousands" of Ukrainians had also been deported to Russia.
Horrific pictures that emerged from Bucha, outside Kyiv, showed bodies strewn across streets and corpses buried in shallow graves.
Moscow denied responsibility and claimed the bodies were planted there after Russian troops left the area, but satellite images prove that was untrue.
