Russia's embassy to Britain said on Monday it would regard the Amesbury poisoning incident which has left one woman, Dawn Sturgess dead, as an anti-Russian provocation in the absence of access to the investigation.

Britain's top counter-terrorism officer has said Sturgess died after being poisoned with a nerve agent that also struck a former Russian spy, Sergei Skripal and his daughter Yulia, in March.

"Without access to the investigation files and to our two citizens (the Skripals), we will consider the incidents in Salisbury and Amesbury as an irresponsible anti-Russian provocation by official London," the embassy said in a statement.