The United Kingdom will seek to intensify diplomatic pressure on the Kremlin after naming two Russian military intelligence officers it said were ordered to carry out the Novichok poisoning attack in Salisbury.
Britain's Security Minister Ben Wallace has said that the Russian President Vladimir Putin is "ultimately responsible" for the deadly Salisbury nerve agent attack as a result of his firm grip on the Russian state.
On Thursday, UK officials laid out the case against Moscow in a meeting with the UN Security Council, of which Russia is a member.
Moscow on Thursday rejected Britain's claims against the Kremlin.
"For us any sort of accusation regarding the Russian leadership is unacceptable," Kremlin spokesman Dmitry Peskov told journalists.
Peskov added that Russia had no intention of investigating the two officers named by British as prime suspects.
In a Commons statement on Wednesday, UK Prime Minister Theresa May vowed revenge on Russia and said there was a threat to "all our allies and to all our citizens" and promised to do "whatever is necessary to keep our people safe".
The prime minister revealed that Britain's security and intelligence services had established that the men, who used the names Alexander Petrov and Ruslan Boshirov, were Russian military intelligence GRU (foreign intelligence) agents and key suspects in the poisoning of the former Russian double agent Sergei Skripal, 67, and his daughter, Yulia, 34, with a nerve agent on March 4.
Local woman Dawn Sturgess died and her boyfriend Charlie Rowley was sickened after they came across remnants of the poison in a discarded perfume bottle in June.
Moscow has always denied involvement in both cases and has accused Britain of manipulation. Maria Zakharova, a Russian Foreign Ministry spokeswoman, said: "The names, as well as the photos, published in the media mean nothing to us."
The ministry said the statement from May was "absolutely unacceptable".
"It contains a number of peremptory accusations against Russia and two of our citizens. We strongly reject these insinuations," the ministry said.
Speaking on the Rossiya-1 TV channel, Zakharova said that Britain should provide fingerprints of the suspects to Interpol as these people allegedly from Russia must have received British visas.
The poisoning case triggered a diplomatic crisis, with Russia and Western countries mutually expelling a large number of diplomats. The United States has also imposed massive economic sanctions against Russia over the incident.
But there is limited appetite among Britain's European allies for further sanctions against Moscow.