Iranian officials have insisted that Syria’s Assad regime has never used chemical weapons, defying evidence linking Damascus to chlorine and nerve agent attacks since 2013.

Addressing a ceremony on the 30th anniversary of an Iraqi chemical attack against the Iranian city of Sardasht, Defense Minister Hossein Dehqan (pictured) proclaimed, “The Islamic Republic of Iran announces that the Syrian government is not after using chemical weapons and this claim by some individuals who regard themselves as the rulers of the world is questionable.”

Iran and Russia, both essential allies of the Assad regime, have been put on the defensive by the reconfirmation that sarin was used in an April 4 assault on the town of Khan Sheikhoun in northwest Syria, which killed at least 92 people and wounded almost 600. The report of the Organization for the Prohibition of Chemical Weapons, based on samples taken from the victims and witness testimony, is expected to be made public on Wednesday.

Intelligence from satellite imagery, radar tracking, and witnesses has established that a regime Su-22 jet dropped a munition with the nerve agent on Khan Sheikhoun, but Dehqan maintained on Sunday that the Syrian army “has never used them (chemical weapons), anytime, anywhere, and will not do so in the future”.

The Defense Minister blamed countries such as the US, UK, and Italy, saying they were putting out propaganda to cover their “3,000 to 4,000 sorties” over the region. He asserted that “some countries” were cooperating with “Takfiris” — a general label covering groups from the Islamic State to Syria’s rebels — over the use of weapons of mass destruction.