In the wake of the nerve agent attack in Salisbury, England, an intelligence chief pledged to fight back.
Moscow has cast doubt over the relevance of the footage showing two Russian nationals visit the U.K., travel to Salisbury and leave during the attack.
Prosecutors in the U.K. are prepared to file an extradition request for two Russians they suspect carried out a nerve agent attack that killed one person and injured three others.
Police are combing thousands of hours of closed-circuit TV footage.
The Russian government previously accused British intelligence officials of carrying out the Skripal poisoning as a way to stir up anti-Moscow sentiment.
Reports suggest the 44-year-old and her partner handled a contaminated item.
The man and woman who fell ill in Amesbury were exposed to the same nerve agent that hospitalized a former Russian agent and his daughter.
The ex-Russian spy and his daughter were hit with an attack that used 50-100 grams of Novichok, the head of the OPCW has said.
Vladimir Uglev identified the poison that hospitalized former double agent Sergei Skripal as Novichok.
The man who may have invented the poison that took down Sergey Skripal has said he supports the British government's stance on Russia.
Sergei Skripal is "improving rapidly," while his daughter can now look forward to leaving hospital.
State Department spokeswoman Heather Nauert said Russia was like a beast with "long arms" and "lots of tentacles."
Sergei Skripal and his daughter are being kept heavily sedated and are still unable to communicate two weeks after they were poisoned.
The scientist Vladimir Uglev helped develop the nerve agent at the centre of the poisoning of the ex-spy and his daughter in Britain.
The back-and-forth blame has continued between British and Russian officials since the March 4 incident.
The foreign ministers of both countries took aim at each other.
Joint statement from the U.S., U.K., France, and Germany decries the "assault on U.K. sovereignty".