France's foreign minister on Wednesday (April 26th) claimed that French intelligence services have scientific proof that the Syrian regime was responsible for a chemical attack that killed 87 people, AFP reported.

Jean-Marc Ayrault said analysis of samples taken at the scene of the April 4th attack in opposition-held Khan Sheikhun showed "there is no doubt that sarin gas was used" and that it was produced by Syrian laboratories.

"There is no doubt about the responsibility of the Syrian regime given the way that the sarin used was produced," Ayrault said after the report was presented at a meeting of French defence chiefs.

He said the substance France believes was used in the attack contains hexamine, a component that also was found in a gas attack in north-west Syria in 2013.

"We are able to confirm that the sarin used on April 4th is the same sarin that was used in an attack in Saraqeb on April 29th, 2013," he said.

Ayrault said the chemical fingerprint is "typical of the method developed in Syrian laboratories".

A French diplomat said the analysis was carried out on unexploded ordnance found at Khan Sheikhun.