The Kremlin makes its bluntest accusation yet over the global solidarity with Britain's view the Skripals were poisoned by Russia.
The Russian foreign ministry also said in the absence of that evidence it will consider the case a murder attempt on Russian citizens as part of a "massive political provocation".
Russia's accusation is its bluntest yet as it continues to deny involvement in the poisoning of former double agent Mr Skripal and his daughter Yulia in Salisbury on 4 March.
The comments come two days after countries across the world started expelling Russian diplomats in solidarity with Britain's view that the Russian state poisoned the pair with a Soviet-designed nerve agent called Novichok.
Montenegro, a former close Russian ally, is the latest country to expel a Russian diplomat.
A total of 25 other nations - including most in Europe, as well as Canada, the US and Australia - have jointly expelled more than 130 diplomats.
The Kremlin on Wednesday reiterated that Russia will "definitely retaliate" against the West over the expulsions.
Russia's ambassador to Australia, speaking a day after the country expelled him, said the world will enter into a "Cold War situation" if the West continues what he alleged is bias against Moscow.
Grigory Logvinov said: "The West must understand that the anti-Russian campaign has no future.
Washington has called on Russia to "accept responsibility for its actions and to demonstrate it is capable of living up to its international commitments".
British Home Secretary Amber Rudd said she has asked about visas granted to Russians working in the UK.
She said she has requested a possible review of Tier 1 visas - for highly-skilled migrants - for Russians who have applied and those who already have one.
A Kremlin spokesman said Russian President Vladimir Putin "remains open" to holding a summit with Donald Trump, despite his US counterpart expelling 60 diplomats.
"This depends on the American side, but the Russian side remains open," Dmitry Peskov said.
"Putin is ready and the Russian side is ready for mutually beneficial and mutually trustful relations with all countries including the US to the extent that our opponents or partners are ready for this."