"This story was straight away used to boost an anti-Russian campaign in the media," foreign ministry spokeswoman Maria Zakharova told reporters.
Ex-double agent Sergei Skripal and his daughter Yulia are in critical condition in hospital after being exposed to an unknown substance, which led them to collapse on a bench in the southwestern English city of Salisbury on Sunday.
Several British news outlets have pointed the finger at Russia and Boris Johnson, Britain's Foreign Minister, promised the UK would "take whatever measures we deem necessary" if Moscow was found to be behind the incident.
"This affair will end up as usual: first, baseless accusations, then it will all be classified and neither journalists nor the people nor the politicians will actually know what happened," she added.
More From This Section
Yesterday, Zakharova called Johnson's statements "wild".
"How can a man charged with foreign affairs, who has no relation to security organs, make such statements?" she said.
Skripal was a former colonel in Russian military intelligence who spied for Britain and moved there in a spy swap in 2010.
British authorities have yet to publicly identify the source of the Salisbury poisoning, but experts said it was unlikely to be radiation as in Litvinenko's case.