"I stress to you once again: the Syrian army has not, did not and will not use this kind of weapons -- not just against our own people, but even against the terrorists that attack our civilians with their mortar rounds," he said, AFP reported.
Muallem spoke at a press conference in Damascus two days after a suspected chemical attack left at least 86 people dead in the rebel-held town of Khan Shaykhoun in northwestern Syria.
"The first air raid conducted by the Syrian army was at 11:30 am (0830 GMT) on that day (Tuesday) and it attacked an arms depot belonging to Al-Nusra Front (also known as Jabhat Fatah al-Sham) that contained chemical weapons," he said.
"Al-Nusra Front and ISIS (Daesh) and other organizations continue to store chemical weapons in urban and residential areas," Muallem added.
The United States and its allies were quick to accuse Syrian government forces of carrying out the attack. The Syrian army said, however, that “it has never used them (chemical weapons), anytime, anywhere, and will not do so in the future.”
Staffan de Mistura, UN special envoy for Syria, said reliable evidence would be needed to confirm the alleged use of chemical weapons, let alone establish who was responsible for it.
“We have no yet any official or reliable confirmation,” he said on Wednesday. “We will be stimulating all those who have the capacity of finding out technically what had happened.”
EU foreign policy chief Federica Mogherini also said there was no evidence yet to draw any conclusion on what had happened in the Idlib governorate, but claimed that the Syrian government held “primary responsibility” for the situation.
Experts point out that the Syrian Army had no rational reason for using chemical weapons against terrorists in Idlib.
The incident in Khan Shaykhun happened days after Washington stated that ousting Syrian President Bashar Assad was no longer a priority for the US. The “Assad must go” premise was one of the cornerstones of Washington’s Syrian policy under Barack Obama. The Trump administration has been dismantling many of Obama’s policies.