A video purporting to show victims of an alleged chemical attack in Syria has been accused of being fabricated, Russian news said today.

Britain, France and the US launched missile strikes against Syria last Saturday in retaliation for an alleged gas attack in Douma they said was carried out by the Syrian government.

The widely circulated video which they claimed showed victims of the gas attack was used as evidence for the action.

However, in an interview released by the Russia 24 news site, 11-year-old Hassan Diab, who is believed to have appeared in the film, said it had been faked by the pseudo-humanitarian organisation White Helmets.

In the exclusive interview he explains how he had been hiding in the basement of the family home with his mother who told him they did not have any food to eat.

“We heard a cry outside calling ‘go to the hospital.’ We ran to the hospital and as soon as I entered, they grabbed me and started pouring water on me," he said.

His father Omar Diab was working on a construction site when he found out his family were at the local hospital. He explained that he had not heard news of a chemical attack.

"There were no chemical weapons. I smoked outside and felt nothing. I entered the hospital and saw my family. Militants gave them dates, cookies and rice for participating in this film and released everyone to their homes," he said. 

Baraa Badran, a doctor who is reported to have been working in the hospital at the time of the alleged attack, claimed that no patients arrived with chemical weapons-related symptoms that day, although many presented with respiratory problems from dust inhalation.

The claims cast further doubt on alleged events in Douma on April 7. Britain, France and the US insist they have evidence of a chemical attack carried out by the Syrian government while Russia claims that the attack was faked by British intelligence services to justify intervention.

The Syrian army reported the discovery of a mass grave in Douma today, finding 30 bodies they said were the victims of the Jaish al-Islam jihadist group which had held the city before surrendering earlier this month.

OPCW inspectors are waiting for clearance to enter Douma to carry out investigations.