"The fact that the British authorities continue to [mention] the unproven involvement of Russia in the poisoning [of Sergei Skripal and his daughter]… is regrettable", the official said, commenting on statements by UK Home Secretary Sajid Javid.
On Monday Javid said that since the attack in Salisbury the Home Office had been reviewing laws related to "hostile state activity".
In March 2018 former Russian military intelligence officer Sergei Skripal and his daughter Julia were found unconscious on a bench near a shopping centre in Salisbury. London claimed they were poisoned with a military-grade nerve agent and accused Moscow of staging the attack. Moscow has repeatedly refuted all accusations.
According to the paper, the prosecution believes that Russian nationals Alexander Petrov and Ruslan Boshirov, suspected by London of poisoning the Skripals, had a "backup team".
Later on Monday, a police spokesperson said that the UK police continue to investigate the incident but were not going to disclose any further details or comments on the recent media report.