"Very serious accusations of ultimatum nature were brought against us. We do not forgive such things. We will work very actively within the legal framework, certainly," Russian Ambassador to the UK Alexander Yakovenko told the Russian NTV channel.
The ambassador stressed that London did not provide any facts on the Skripal case.
READ MORE: May Heckler Demands 'Clear Evidence' Russia Behind Skripal Poisoning
The UK-Russian relations deteriorated in early March after former Russian intelligence officer Skripal and his daughter were found unconscious in a shopping center in Salisbury.
UK Prime Minister Theresa May said that it was "highly likely" that Russia was responsible for the incident and later went on to announce a package of anti-Russian measures, including the expulsion of 23 Russian diplomats from the country, and the suspension of bilateral contacts between London and Moscow.