U.K. Prime Minister David Cameron told the BBC that the U.K. had fresh evidence of the use of chemical weapons near Damascus on August 21.
CNN is reporting that the U.K. is now saying that clothing samples taken from the site of the attack in the suburbs of the capital test positive for sarin.
A British source told AFP that a soil and cloth samples have "tested positive for sarin."
The Independent also reports that soil and clothing collected for the site and tested at the secret Porton Down laboratories contained traces of sarin gas.
Sarin is a nerve toxin so deadly that just one drop can kill a grown man. The fatality typically comes from cardiac arrest or suffocation, as overstimulated muscles around the heart and lungs eventually seize and stop working altogether.
Last week, U.S. Secretary of State John Kerry said that sarin was used in the attack, which the U.S. estimates killed 1,429 people and caused "neurotoxic symptoms" in thousands of others.
The Obama administration is currently trying to convince Congress to approve a strike on the Syrian government in response to the chemical attack.
SEE ALSO: This Is What Happens To Someone Hit By The Nerve Toxin Allegedly Used By Assad