The Syrian army has accused the US-led coalition of launching an air strike on Wednesday evening that hit an Islamic State (IS) chemical weapons supply, killing “hundreds including many civilians.”

Accusation follows a week after Syrian government was accused of launching its own chemical attack.

Syrian state-run news agency Sana reported the air strike, on the village of Hatla, as a “white cloud that became yellow as a result of the explosion of a huge store that includes a large amount of toxic materials”.

A statement on behalf of the Syrian army said the bombing at around 5:30 pm local time (3:30 pm 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.

“The jets of the so-called US-led coalition launched a strike at about 17:30-17:50 on a Daesh warehouse where many foreign fighters were present.  First a white cloud and then a yellow one appeared at the site of the strike, which points at the presence of a large number of poisonous substances.  A fire at the site continued until 22:30,” the statement from the Syrian General Staff reads.

The incident proved that IS and al Qaeda-linked militants "possess chemical weapons", the statement said. 

The British online newspaper The Independent says there was no immediate independent confirmation or reaction from the US coalition, which has operated in the skies above Syria since 2014.