Russia has announced the expulsion of 23 British diplomats as a row escalates with London over a nerve-agent attack on a former double agent, Sergei Skripal, and his daughter on British soil.

The Foreign Ministry in Moscow said the move was in retaliation of Britain’s decision to expel the same number of Russian diplomats on Wednesday.

Britain’s action was sequel to the use of a Russian-developed nerve agent to poison Skripal and daughter.

Russia had been expected to hit back at Britain, after Foreign Minister Sergei Lavrov had said on Friday that his country intended to expel British diplomats.

The British Council has also fallen victim to the escalating tensions, with Moscow on Saturday withdrawing its permission for the cultural institute to open a location in St. Petersburg.

The Council has been ordered to cease all operations in Russia, with the Foreign Ministry citing its “unregulated status.”

Russia has threatened to escalate its response should Britain respond with further sanctions, according to the ministry statement.

Mr. Skripal, who was convicted in Russia of selling state secrets to Britain, and his daughter Yulia were poisoned in the southern city of Salisbury. Both are in critical but stable condition in hospital.

Russia has come under growing pressure from Britain and its allies, after Prime Minister Theresa May said it was “highly likely” that Moscow was responsible for the attack.

British Foreign Secretary Boris Johnson told reporters that it was “overwhelmingly likely” that Putin himself ordered the attack.

The Kremlin, however, has repeatedly denied any involvement and dismissed Mr. Johnson’s accusation as “shocking and inexcusable.”

Responding to Russia’s decision to expel the diplomats, Britain said it had “anticipated” the move.

The government in London “anticipated a response of this kind and the National Security Council will meet early next week to consider next steps,” a statement from the Foreign Office said.

A ministry spokesman said Britain’s first priority would be in helping those who would be returning to Britain.

He reiterated Britain’s position that there was “no alternative conclusion other than that the Russian State was culpable” in the attack in Salisbury.

““We have no disagreement with the people of Russia and we continue to believe it is not in our national interest to break off all dialogue between our countries.

“”However the onus remains on the Russian state to account for their actions and to comply with their international obligations,” the spokesman said.

(dpa/NAN)