British intelligence officials believe that the alleged March 4 poisoning of ex-Russian security officer Sergei Skripal and his daughter Yulia was ostensibly approved by Russia's President Vladimir Putin, CNN reported, citing unnamed sources.
According to the media report, a UK official claimed that "it's above the [Russian military foreign-intelligence service] GRU leadership" and that "what that actually means, we can have a good guess."
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The allegations, which haven't yet been commented on either by Moscow or by London, come after Russian Foreign Minister Sergey Lavrov pointed out that the fact that it remains unclear where the Skripals currently are proves that the UK government and intelligence has "something to hide" about the matter.
"Where is Yulia Skripal, and where is her father — these are our main questions today. They have not been shown to the public for many months already," Lavrov said.
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He recalled that recently a new BBC documentary on the investigation into Skripal case had been released, but that "not a single word has been said about them [in the film]."
The statement followed the Russian Embassy in London stating that they had sent another formal letter to the UK's Foreign Office asking for information about the Skripals. The embassy also signalled Russia's readiness to "demand that British authorities provide detailed information about the [Skripal] incident, grant consular access to the Russian citizens and begin a joint investigation."
"The document stresses that London has blatantly violated international rules by ignoring Russia’s vested right to obtain information on its citizens who have been held in isolation … at an undisclosed location," the embassy stressed.
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Russian presidential spokesman Dmitry Peskov, for his part, bemoaned the fact that London rejected Moscow's proposal "to cooperate with the British side to clarify the circumstances of this [Skripal] incident."
"We were not met with reciprocity, and we do not have any information about what happened in Salisbury. We do not have information about what kind of agent was used, how much of it there was, what its volume was; we do not have information about who was poisoned, what happened to them, where they disappeared to, etc.," Peskov emphasized.
His comments came after the London Metropolitian Police released fresh CCTV footage which showed the two Russian nationals it suspects of involvement in the Skripals' poisoning walking around the southern English town of Salisbury on March 4. The footage does not show the men at Skripal's home, however, where police allege they sprayed a military-grade poison on the door handle.
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Earlier, UK Prime Minister Theresa May accused Russian military intelligence service GRU of orchestrating the poisoning under the order of Russian authorities.
Earlier, the UK and its allies have accused Moscow of having orchestrated the Skripal attack with what UK experts claim was the A234 nerve agent, without presenting any proof. Russian authorities have strongly refuted the allegations as groundless.