While investigators accused the Syrian regime of sarin attacks in 2017, Moscow was urged by Western nations to reveal the circumstances of Alexei Navalny's nerve agent poisoning.
Russian Foreign Minister Sergei Lavrov says ex spy poisoning could be 'in interests' of UK government
Lavrov also suggested that the poisoning of Skripal could also be in the interests of the British special forces who are known for their abilities to act with a licence to kill".
In Washington, the State Department said there was no justification for the Russian move and that the United States "reserves the right to respond."
Britain's foreign ministry and the Russian embassy in London have been doing battle on social media over the death of ex-double agent Sergei Skripal.
The United States agreed with its ally Britain on Tuesday that Russia was probably behind an attempt to poison a former double agent, saying the perpetrators should face punishment.
Britain was to hold a second meeting of its national emergencies committee on Saturday in response to a nerve agent attack on a Russian former spy.