The letter was published by the Russian Foreign Ministry on Sunday, a day after similar questionnaires were forwarded to the foreign departments of the UK and France. In a statement on its website, the ministry again stressed that the whole Skripal case was "fabricated against Russia."
The 13 questions, sent by Russia's permanent mission at the Organization for the Prohibition of Chemical Weapons (OPCW) to the watchdog's Technical Secretariat, can be divided into broader groups that address three important aspects of the ongoing investigation: the UK's dealings with the OPCW, the OPCW's procedure and France's involvement in the investigation.
What does Britain want from the OPCW?
The first several questions deal with the assistance that the OPCW provided to the British in the investigation.
"What exactly is Britain asking the OPCW Technical Secretariat to confirm: only the fact that a nerve agent was used or that it belongs to the 'Novichok' type under Western classification?" one of the questions reads.
Moscow is also asking what type of samples and other evidence was handed over to the OPWC by the British and whether the Technical Secretariat has plans to share its information on the Skripal case with the OPCW Executive Council, of which Russia is a member.