Russia's Foreign Minister Sergei Lavrov said Tuesday that Moscow "has no connection" to a deadly nerve agent used to attack a former Russian spy and his daughter in the U.K.
Lavrov said Russia had requested access to the nerve agent used in the March 4 attack in Salisbury, England, but had been denied access "to materials related to the Skripal case," Reuters reported.
U.K. Prime Minister Theresa May said Monday that it was "highly likely" that Russia was responsible for the attempted murders of Sergei Skripal and his daughter Yulia.
Stressing that Russia had no connection to the poisoning, Lavrov said he expected London to reply to Moscow's request to open up the investigation as Yulia is a Russian citizen.
Lavrov's comments come after Russia was given a deadline — the end of Tuesday — to explain why a nerve agent, which the U.K. deemed to have been created in Russia, was used to poison the Skripals.
Calling it a "reckless and despicable act," May said Monday: "There are therefore only two plausible explanations for what happened in Salisbury on March 4. Either this was a direct act by the Russian state against our country. Or the Russian government lost control of this potentially catastrophically damaging nerve agent and allowed it to get into the hands of others."
May said U.K. Foreign Secretary Boris Johnson had summoned the Russian ambassador to the Foreign and Commonwealth Office to explain why the nerve agent was used in the poisoning. Moscow has until the end of Tuesday to respond, she said.
May hinted that Britain is "ready to take much more extensive measures" against Russia, beyond the commonplace expulsion of diplomats, visa freezes and suspended security cooperation.
Offering his support to the U.K. government, the now-ex U.S. Secretary of State Rex Tillerson said Monday "the attempted murder of a private citizen on the soil of a sovereign nation" was never justified.
"And we are outraged that Russia appears to have again engaged in such behavior. From Ukraine to Syria — and now the U.K. — Russia continues to be an irresponsible force of instability in the world, acting with open disregard for the sovereignty of other states and the life of their citizens," he said in a statement.
France's President Emmanuel Macron and the European Union have also offered the U.K. their support.
Skripal and his daughter remain in a critically ill condition in hospital. The pair were found slumped on a bench in Salisbury city center and parts of the city have since been cordoned off as British counter-terrorism police and the army have sought the source of the nerve agent.
Speaking to the U.K. parliament on Monday, May said the nerve agent used was part of the Novichok family of deadly chemical weapons. It is far more toxic than nerve agent VX, which was used to murder Kim Jong-un's half-brother Kim Jong Nam in 2017. "Novichok" means "newcomer" in Russian and such nerve agents were developed in the country a few decades ago.
"It is now clear that Mr Skripal and his daughter were poisoned with a military-grade nerve agent of a type developed by Russia," May said. "This is part of a group of nerve agents known as 'Novichok.'"
Skripal was a former Russian spy turned double agent for the U.K. intelligence services. He had settled in Salisbury following a "spy swap" in 2010 that saw him released from prison in exchange for Russian spies in the U.S.
He is not the first former agent to be pursued, allegedly, by the Russian state. Alexander Litvinenko, a former secret service officer in Russia, was murdered in London in 2006 after his cup of tea was laced with polonium.
On Monday, May said the most recent attack had been carried out "against a backdrop of a well-established pattern of Russian state aggression."
"Russia's illegal annexation of Crimea was the first time since the Second World War that one sovereign nation has forcibly taken territory from another in Europe," she said.
"Russia has fomented conflict in the Donbas, repeatedly violated the national airspace of several European countries, and mounted a sustained campaign of cyber espionage and disruption. This has included meddling in elections, and hacking the Danish Ministry of Defense and the Bundestag, among many others."
She also mentioned Litvinenko's death and how the U.K. could respond with more sanctions against Russia.
"Russia used radiological substances in its barbaric assault on Mr Litvenenko. We saw promises to assist the investigation then, but they resulted in denial and obfuscation — and the stifling of due process and the rule of law."
Following Litvinenko's death, the U.K. expelled Russian diplomats, suspended security co-operation, broke off bilateral plans on visas, froze the assets of the suspects and placed them on international extradition lists, May said. This time, the U.K. could go further.