Information about the possible use of chemical weapons by Russian occupiers in the besieged Mariupol is currently being checked by Australia and its partners, Australian Foreign Minister Maris Payne said.

"Reports Russian forces may have deployed a chemical agent in Mariupol are deeply concerning. Australia is working with partners to verify these reports. Any use of chemical weapons would be a further wholesale breach of international law, " Payne said on Twitter Tuesday.

As reported, on the evening of April 11, the Azov regiment said that the Russian occupation forces dropped a toxic substance of unknown origin from an unmanned aerial vehicle on Ukrainian military and civilians in Mariupol.

The regiment also noted that the victims have respiratory failure, vestibulo-atactic syndrome. The consequences of using an unknown substance are being clarified.

Leader of Azov Andriy Biletsky reported three victims. "A few hours ago, the Russians struck Mariupol with chemical weapons, at the Azovstal plant - at the fortress of Ukrainian fighters, Azov members. If we talk about the practical side of the blow, it is small. Three people have clearly expressed signs of chemical poisoning, but without catastrophic consequences," he said in a video message on Tuesday night.

Later, British Foreign Secretary Liz Truss said that the country was working with partners to verify details about the possible use of chemical weapons in Mariupol.

Deputy Head of the Ministry of Defense of Ukraine Hanna Maliar also said that information about the possible use of chemical weapons by the occupiers in Mariupol is being checked by the Ukrainian authorities.