UK minister says Russian chemical attack would draw Western 'response'

The stark warning came hours after London said it was trying to verify reports Moscow used chemical weapons on Monday in the besieged Ukrainian city of Mariupol

A U.K. minister warned on Tuesday any use of chemical weapons by Russia in its attacks on Ukraine "will get a response and all options are on the table".

The stark warning came hours after London said it was trying to verify reports Moscow used chemical weapons on Monday in the besieged Ukrainian city of Mariupol.

"If they are used at all, then (Russian) President (Vladimir) Putin should know that all possible options are on the table in terms of how the West might respond," armed forces minister James Heappey told Sky News.

"There are some things that are beyond the pale, and the use of chemical weapons will get a response."

Foreign Secretary Liz Truss said hours earlier that Britain was working with partners to verify the reports that Russian forces may have used chemical agents in Mariupol.

"Any use of such weapons would be a callous escalation in this conflict and we will hold Mr. Putin and his regime to account," she added on Twitter.

Reports first emerged earlier on Monday from Ukraine's Azov battalion that a Russian drone had dropped a "poisonous substance" on troops and civilians in Mariupol.