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Britain's representative to the global chemical weapons watchdog told a meeting of the organization on Wednesday that London continues to believe Russia is to blame for the nerve agent attack on former Russian spy Sergei Skripal and his daughter, and warned that repeated uses of chemical weapons in recent months threaten to undermine the treaty that bans such arms.

'We believe that only Russia had the technical means, operational experience and motive to target the Skripals," Ambassador Peter Wilson told a meeting of the Executive Council of the Organization for the Prohibition of Chemical Weapons. Wilson's comments to the closed-door meeting in The Hague were tweeted by his delegation.

The meeting was held at the request of Britain following a report by OPCW experts into the March 4 attack on the Skripals in the English city of Salisbury.

Britain blames Russia for the attack, which it says was carried out by smearing a Soviet-developed nerve agent known as Novichok on a door handle at Sergei Skripal's house. Moscow denies involvement.

In a summary of its report published last week, the OPCW did not name Novichok, but it confirmed "the findings of the United Kingdom relating to the identity of the toxic chemical that was used in Salisbury."

Wilson told Wednesday's meeting that Russia "has a proven record of conducting state-sponsored assassination. It is highly likely that the Russian intelligence services view at least some of its defectors as legitimate targets for assassination."

Wilson warned of the Chemical Weapons Convention being undermined by a growing use of nerve agents and other poisons, mentioning the 2017 assassination in Malaysia of North Korean leader Kim Jong Un's estranged half-brother alongside the Salisbury attack.

"In the past 14 months, we have seen the use of chemical weapons in Syria, in Iraq, in Malaysia and now in the U.K.," Wilson said. "This is a serious threat to the CWC."