Russian government, through its foreign ministry, has accused the British government of using one-sided and non-transparent methods to investigate the attempted murder of Sergei Skipal, a former Russian spy and has threatened to retaliate.
Britain had earlier expelled 23 Russian diplomats from the UK.
“Naturally, our countermeasures won’t keep you waiting,” Russia announced in a statement.
“Instead of completing its own investigation, using existing international formats and instruments, including those under the authority of the organisation for the prevention of chemical weapons, which is what we were prepared for, the British government has made the choice to confront Russia.
“Obviously, by using one-sided and non-transparent methods to investigate this incident, the British authorities are trying to concoct yet another unfounded anti-Russian campaign.”
The Russian embassy, too, had earlier described the expulsion of the diplomats as unacceptable, unjustified and shortsighted.
Theresa May, UK’s prime minister, had expelled Russian diplomats who, allegedly, tried to kill Skripal.
Skripal, a former Russian spy in the UK who, after selling information to the UK, was sentenced for espionage in 2006. Skripal and Yulia, his daughter were found unconscious on a bench outside a shopping centre in Salisbury, in southern England, and reports say they have been poisoned with highly dangerous substance.
Speaking at the house of commons May told members of parliament that it was an unlawful use of force by the Russian state against the United Kingdom which demanded a full and robust approach.
May explained that Russian President Vladimir Putin had responded to her demand to explain the reckless and despicable act in Salisbury with sarcasm, contempt and defiance.