Britain's claim that Moscow was behind the poisoning of a former Russian spy is facing fresh scrutiny.
It's emerged the UK government's deleted a tweet blaming Russia for producing the nerve agent used in the attack.
The attack a month ago - on Sergei Skripal and his daughter in Salisbury - has triggered a wave of tit-for-tat expulsions of diplomats around the world.
The UK Foreign Office acknowledges it removed the social media post.
However, it says the decision to delete doesn't change the UK government's assessment that Russia was responsible for the "brazen and reckless act".