The UK is expected to unveil new sanctions against Russia on Wednesday following the attack on former spy Sergei Skripal and his daughter in the city of Salisbury.
Theresa May, Britain’s prime minister, had given Moscow until midnight on Tuesday to provide a “credible response” or face additional sanctions. The deadline passed without incident.
She will chair a meeting of the UK’s National Security Council on Wednesday morning to discuss “the next steps” that Britain will take in light of Russia’s response.
She is then expected to give a statement in the House of Commons in which she will set out any measures. Possible sanctions include expelling Russian diplomats or laws allowing the government to ban Russians accused of rights abuses from entering the UK.
Moscow has rejected Britain’s ultimatum to explain its alleged role in the attempted murder of Mr Skripal, saying it would need access to details of the investigation into the case before it would respond.
Sergei Lavrov, foreign minister, said on Tuesday that accusations of Russian involvement in the poisoning of Mr Skripal and his daughter Yulia with a Soviet-era nerve agent were “nonsense” and that Russia had “nothing to do with it”. Britain’s ambassador to Moscow was summoned to the Russian foreign minister following Mrs May’s ultimatum.
On Tuesday evening the Russian embassy in London wrote on Twitter: “Any threat to take ‘punitive’ measures against Russia will meet with a response. The British side should be aware of that.”
The prime minister said on Monday it was “highly likely” that Moscow was involved in Mr Skripal’s poisoning and said the government should “stand ready to take extensive measures”.
Amber Rudd, UK home secretary, confirmed on Tuesday that the police and security services would review up to 14 deaths in the UK that may have links with Russia. A BuzzFeed news investigation claimed that 14 Russians, including oligarch Boris Berezovsky, may have been assassinated on British soil.
The review came as Nikolai Glushkov, a Russian exile with close links to Berezovsky, was reported to have been found dead at his London home.
UK police said anti-terrorism police were investigating the death of an unidentified man, believed to be Glushkov, which was being treated as unexplained. They said there was no evidence to suggest a link to the incident in Salisbury.
“Mr Glushkov was obviously Putin’s public enemy. He was a close associate of Boris Berezovsky,” said Alex Goldfarb, a close associate of Berezovsky. “He was sentenced in Russia to a jail term in absentia, and the Russians sought his extradition.
“It is another instance of Putin’s enemies who have been dying one after the other.”
The UK communications watchdog said that Kremlin-backed broadcaster RT, formerly known as Russia Today, could lose its British licences if the poisoning of Mr Skripal and his daughter were found to be an “unlawful use of force” by Russia.
Ofcom said that it had written to the holder of RT’s UK broadcast licences to warn that the regulator would “consider this relevant to our ongoing duty to be satisfied that RT is fit and proper”.
Russia said it would retaliate against UK media in Russia if RT were shut down.
Mr Lavrov said that Russia would only act under terms set by the Chemical Weapons Convention, which give respondents 10 days to face accusations of producing chemical weapons used abroad.
Mr Skripal, a former Russian agent who passed secrets to Britain’s foreign intelligence service MI6, and his daughter remain in a serious condition after being taken ill on March 4.
Just before being sacked as US secretary of state, Rex Tillerson led western condemnation of the attack.
He described the use of a nerve agent as a “really egregious act” which appeared “clearly” to originate from Russia and would “certainly . . . trigger a response”.
Mrs May discussed the case with Donald Trump, US president, who said “the US was with the UK all the way, agreeing that the Russian government must provide unambiguous answers as to how this nerve agent came to be used”.
Angela Merkel, German chancellor, who spoke to Mrs May, condemned the attack.
“It is up to Russia to provide swift responses to the British government’s justified questions and to comply with the demand to fully and immediately disclose the relevant chemical weapon programme to the Organisation for the Prohibition of Chemical Weapons,” Ms Merkel said.
But the case risks exposing faultlines among the allies, with some European capitals already chafing at the restrictions imposed by EU sanctions against Moscow. Mr Trump has still not imposed a fresh round of sanctions requested by Congress last year.
Mr Tillerson said that it would be “almost beyond comprehension” for a state to be behind the attack with what the UK says is a military-grade nerve agent from a family of chemical weapons called Novichok.
Jens Stoltenberg, Nato’s secretary-general called the use of the nerve agent “horrendous and completely unacceptable”. He said the western alliance was in touch with authorities in the UK, which he called a “highly valued ally”.
Additional reporting by Neil Buckley in London and Guy Chazan in Berlin