Allegations that his forces had deliberately poisoned civilians were ''100 per cent fabrication'', the president said on Thursday, adding that the Syrian government gave up its chemical weapons stocks as part of a 2013 agreement.
“Our impression is that the West, mainly the United States, is hand-in-glove with the terrorists. They fabricated the whole story in order to have a pretext for the attack,” he said.
Mr Assad made the comments in an interview broadcast by AFP, his first since the US struck a Syrian airbase with missiles in retaliation for the events in Idlib province.
The international community has condemned the deaths in the village of Khan Sheikhoun, which most Western intelligence services believe occurred thanks to a deliberate attack carried out by the Syrian government.
Damascus and allies in Moscow have denied the regime attacked the village with chemical weapons, maintaining that the casualties were caused by gases released after an al-Qaeda-affiliated ammunitions depot was hit by conventional munitions in a legitimate government air raid.
Neither country has provided any on-the-ground evidence to back up their claims.
Mr Assad insisted that it is not clear yet what happened during the incident, since evidence touted by the West comes from “a branch of al-Qaeda.” Besides, he added, “how can you verify a video? You have a lot of fake videos now.”
“We don't know whether those dead children were killed in Khan Sheikhoun. Were they dead at all? …The story is not convincing by any means.”
The Syrian government agreed to surrender its chemical weapons stocks to an international watchdog after the deaths of hundreds in a rebel-held suburb of Damascus in 2013, although the opposition has long accused the regime of holding back some of its supply. The Organisation for the Prohibition of Chemical Weapons (OPCW) has said it believes Mr Assad's government is responsible for at least two chemical weapons attacks that have occurred in Syria since then - claims the president also denies.
US President Donald Trump retaliated last Friday with a “warning shot” barrage of 59 Tomahawk missiles which struck the regime-operated Shayrat airbase near Homs – the first direct action against Mr Assad’s forces taken by the US in more than six years of the civil war.
Russian forces present at the base were given advance warning of the strike, which means it caused limited damage to Russian and Syrian air force capabilities despite its ferocity. Six Syrian servicemen were reported as dead in the incident.
On Wednesday, Russia's representative to the United Nations vetoed a Security Council resolution condemning the Khan Sheikhoun attack and recommending an immediate international investigation.
The draft text called on the Syrian government to provide flight plans, flight logs and other operational military information from the day of the strike.
Any investigation would have to be impartial, Mr Assad said, adding: “When we make sure that unbiased countries will participate in this delegation in order to make sure that they won't use it for politicised purposes.”
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies