The British online newspaper The Independent says the United States has denied a claim by the Syrian army that American-led coalition jets launched an air strike that hit an Islamic State chemical weapons supply, killing "hundreds including many civilians".

A statement on behalf of the Syrian army said the bombing at around 5.30pm local time (3.30pm BST) on Wednesday in the eastern Deir al-Zor province hit the terror group’s stockpile, without giving details of which toxic substance it might be.

But US Air Force Colonel John Dorrian, a spokesman for the America-led coalition, said it had carried out no air strikes in that area at the time.

“The Syrian claim is incorrect,” he told Reuters, accusing the regime of deliberately spreading “misinformation.”

There has been no independent confirmation of the alleged attack by the US-led coalition, which has operated in the skies above Syria since 2014 and includes British, French and German contributions, according to The Independent.