Damascus has repeatedly denied any involvement in the incident and said that the Syrian government doesn't possess chemical weapons as the full destruction of Damascus’ chemical weapons stockpile had been confirmed by the Organization for the Prohibition of Chemical Weapons (OPCW) in January 2016.
"The US version regarding an aerial bomb being dropped from a Syrian air force plane raises serious doubts," Mikhail Uliyanov told Sputnik.
He pointed to footage filmed by the opposition at the site of the April 4 incident in Idlib province as proof that the attack may have been staged.
"Such a high degree of readiness to respond, and not in a metropolis but in a small provincial town with a population of 40,000, suggests that the 'rescuers' were on the scene before it happened," Uliyanov said.
CIA Director Mike Pompeo said Tuesday the US intelligence community possessed strong evidence that the Syrian army used chemical weapons in the Idlib province on April 4.
"References to the presence of irrefutable proof in the American intelligence community, which remain unpresented, do not have any credibility, especially since the memory of the confusion surrounding the 'weapons of mass destruction of Saddam Hussein' is still fresh," Ulyanov said.
He said the US position on the chemical incident in Khan Sheikhoun "raises huge questions" in Moscow. "All of their statements with accusations against the official Damascus are absolutely unsubstantiated," Ulyanov added.
In an interview with Sputnik on April 21, Assad characterized the alleged chemical attack in Khan Sheikhoun as a provocation to justify the US strike on Ash Sha’irat. The Syrian leader also warned of the possibility of the new provocations similar to the one in Khan Sheikhoun.