Inspectors from the world's chemical weapons watchdog on Monday began examining the poison used to strike down a former Russian double agent in England, in an attack that London blames on Moscow.
Britain says Sergei Skripal and his daughter, who are critically ill in hospital, were targeted with the Soviet-era, military-grade nerve agent Novichok. It accuses Moscow of stockpiling the toxin and investigating how to use it in assassinations.
Russian President Vladimir Putin, who easily won another six-year term on Sunday, said the claims were nonsense and that Russia had destroyed all its chemical weapons. While the Kremlin told Britain to back up its assertions or apologize, Britain's fellow EU members offered it "unqualified solidarity."