Police appeal for more information about chemical weapons attack that nearly killed double agent Sergei Skripal in 2018.
Russia, meanwhile, accuses US of using its relationship as political football ahead of presidential elections.
The head of British foreign intelligence set to deliver speech warning Russia should not underestimate UK capabilities.
The man was identified as Alexander Mishkin, a doctor working for the Russian GRU intelligence service.
An overview of recent allegations against intelligence agency GRU after series of announcements by Western nations.
US indictments follow Dutch revelations of alleged disrupted Russian hacking attempt against chemical weapons agency.
In his toughest remarks on the poisoning case to date, Russian president says Skripal is a “traitor to the homeland”.
Two Russian men accused of trying to kill a former Russian spy in Salisbury deny being military intelligence officers.
Russian president says Moscow knows identity of the two men accused by UK of attempting to murder former double agent.
UK envoy to UN says British government has ‘clear evidence’ of Russian state involvement in failed assassination.
London has accused two members of Russian military intelligence of using Novichok to try to kill a former Russian spy.
Prosecutors name two Russians as suspects in attempted assassination of ex-spy.