Britain's claim that Moscow was behind the poisoning of a former Russian spy faced fresh scrutiny Wednesday when it emerged the UK government had deleted a tweet blaming Russia for producing the nerve agent used in the attack, CNN reported.

The UK Foreign Office acknowledged it had removed the social media post, which stated that British chemical weapons experts believed Russia made the nerve agent, Novichok, used to poison Sergei Skripal and his daughter Yulia in the English city of Salisbury on March 4.

A Foreign Office spokesperson told CNN that the tweet was removed because it was "truncated and did not accurately report" a briefing by the British ambassador to Moscow last month.