A report by United Nations inspectors examining an purported chemical attack in Syria will "probably" be published on Monday, French Foreign Minister Laurent Fabius said on Thursday Al Arabiya reported.
"It will say that there was a chemical massacre," Fabius told French radio, according to statements carried by Agence-France-Presse.
The U.N. team left Syria on Aug. 31, after collecting samples as part of their probe into an Aug. 21 chemical weapons attack in a suburb of the Syrian capital.
The U.S. and its allies have said the regime of Syrian President Bashar al-Assad carried out the attack, while Damascus and its ally Russia have said the opposition were responsible.
Sources told Reuters that the upcoming U.N. report will not explicitly pin the blame on any parties in the Syrian conflict.
However, their factual reporting alone could suggest which side in the country's civil war was responsible, Reuters said.
The report could easily become a bargaining chip in talks between Moscow and Western powers on conditions for Syria to give up its chemical weapons and the terms of a United Nations Security Council resolution on the matter.
Two Western diplomats said they strongly expected chief U.N. investigator Ake Sellstrom's report would confirm the U.S. view that sarin gas was used in the attack on Damascus that killed hundreds.
The news comes ahead of a Geneva meeting between U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov to discuss the Syrian arsenal of chemical weapons.
Five permanent veto-wielding powers of the U.N. Security Council met in New York on Wednesday to discuss plans to place Syria's chemical weapons under international control as Britain, France and the United States talked about drafting a resolution.