Britain is deeply concerned about Russia’s potential use of chemical weapons in Ukraine, according to British Foreign Minister Liz Truss, who warned that using them would be a catastrophic mistake for Russian President Vladimir Putin.

Russia’s war in Ukraine began a third week with none of its claimed objectives fulfilled, despite thousands of people slain, more than two million made refugees and thousands cowering in besieged cities under unrelenting bombardment.

Truss stated, “We are quite concerned about the possible use of chemical weapons.”

“We’ve seen Russia employ these weapons in battle before, but that would be a severe error on Russia’s behalf, on top of the awful mistakes Putin has already done.”

The remarks came a day after the US refuted repeated Russian allegations that it was running biowarfare facilities in Ukraine. The assertions were described as “laughable,” and it was believed that Moscow was preparing to unleash a chemical or biological weapon.

On Thursday, Britain’s armed forces minister, James Heappey, was questioned if using chemical weapons would cross a’red line,’ causing NATO nations to become engaged in the battle.

“I don’t believe it’s good to get into any precise commitments about where that red line stands right now,” he told BBC radio. “But I think President Putin has to make very clear that when other nations use chemical weapons, it causes an international response,” he said.

“I think he (Putin) should reflect very urgently on what has happened to other countries where they have used this.”