Volunteer first responders and activists said a chemical attack by the Syrian government killed at least 70 people in the town of Douma.
The attack prompted international outrage and led Donald Trump to threaten military action.
The UK and France have now backed potential strikes but Moscow warned against any action and threatened to retaliate.
Russian Defence Ministry spokesman, Major General Igor Konashenkov, released statements by medics from Douma’s hospital who said a group of people toting video cameras entered the hospital, shouting that its patients had been struck with chemical weapons and causing panic.
The medics said none of the patients were hurt by chemicals.
Maj Gen Konashenkov said Britain was “directly involved in the provocation”.
He said: “”We have .. evidence that proves Britain was directly involved in organizing this provocation.”
Russia’s foreign minister Sergey Lavrov said earlier that Russian experts had inspected the site of the claimed attack and found no trace of chemical weapons.
As fears of a Russia-West military confrontation mounted, French President Emmanuel Macron expressed his “deep concerns” over the situation in Syria in a phone call with Russian President Vladimir Putin.
According to a statement by the French presidency, Mr Macron called for dialogue between France and Russia to “continue and intensify” to bring peace and stability to Syria.
The Kremlin said Mr Putin warned against rushing to blame the Syrian government before conducting a “thorough and objective probe”.
The Russian leader warned against “ill-considered and dangerous actions … that would have consequences beyond conjecture”.
Mr Putin and Mr Macron instructed their foreign and defence ministers to maintain close contact to “de-escalate the situation”, the Kremlin said.
US President Donald Trump emerged from a meeting with his national security team on Thursday without a “final decision” on how to respond to the suspected chemical attack.
White House spokeswoman Sarah Huckabee Sanders said Mr Trump held a meeting with his team to discuss the situation, but “no final decision has been made”.
She said US officials are “continuing to assess intelligence” and are “engaged in conversations with our partners and allies”.
The Foreign Office said accusations made by Moscow that Britain directed the attack on Douma were “ludicrous”.
A spokesman said: “Russia has wielded its UNSC veto six times since February 2017 to shield the Assad regime from scrutiny for its use of chemical weapons.
“These accusations from Moscow are just the latest in a number of ludicrous allegations from Russia, who have also said that no attack ever happened.
“This simply shows their desperation to pin the blame on anyone but their client: the Assad regime.
“The chemical weapons attack in Douma last Saturday was a shocking and barbaric act that cost up to 75 lives including young children.”
Additional reporting by the Press Association