A suspect in the nerve agent poisoning of a Russian ex-spy in Britain in March is a colonel in Russia's GRU military intelligence agency, investigative website Bellingcat alleges.

Russia's Vladimir Putin says that two men Britain suspects of poisoning former spy Sergei Skripal with military-grade nerve agent had been identified as "civilians" and were not criminals.

British prosecutors yesterday charged two Russians for the attempted murder of a former Russian spy and his daughter with a nerve agent, naming suspects for the first time in a case that has caused one of the biggest East-West rifts in decades.