NEW YORK – In the latest sign of rising tensions between Britain and Russiaover the poisoning of a former Russian spy, the two countries’ envoysclashed at a UN Security Council emergency meeting convened especially overthe matter on Wednesday.

The exchange of barbs came shortly after British Prime Minister Theresa Mayannounced that her government will expel 23 Russian diplomats, cancelhigh-level bilateral contacts with Russia, and freeze Russia state assets”wherever we have the evidence that they may be used to threaten the lifeor property of UK nationals or residents.”

“The Russian Federation thinks it is completely unacceptable to launchunjustified accusations as contained in the letter from Theresa May datedMarch 13 to the secretary-general of the United Nations,” Russia’s UNambassador Vasily Nebenzya said.

“We demand that material proof be provided of the allegedly found Russiantrace in this high-resonance event. Without this, stating that there isincontrovertible truth is not something that we can take into account,” headded.

The London-Moscow row started following the murder attempt on formerRussian double agent Sergei Skripal and his daughter Yulia in Britain’ssouthwestern city of Salisbury.

Found unconscious on a bench outside a shopping center there on March 4,they remain in critical condition.

Britain claims the father-daughter pair was exposed to a nerve agent andRussia is responsible for the act, which Moscow denies.

At the UN Security Council meeting, Britain’s Deputy UN Ambassador JonathanAllen said hundreds of his countrymen had potentially been exposed to theagent.

He said Skripal, a 66-year-old former Russian spy who became a double agentfor Britain, and his 33-year-old daughter were poisoned with novichok, achemical nerve agent that cannot be manufactured without the use of thehighest-grade state laboratories.

“This was no common crime,” he said. “It was an unlawful use of force.”Xinhua