Chemical weapons were likely used on four occasions in Syria, but it remains unclear who was behind the attacks and what materials were used, UN human rights investigators said Tuesday in Geneva, dpa reported.
The UN Commission of Inquiry on Syria also told the UN Human Rights Council that "the conflict in Syria has reached new levels of brutality."
Chemical attacks allegedly took place in the Aleppo and Damascus provinces on March 19, in the city of Aleppo on April 13, and in Idlib province on April 29, the commission said in its latest report.
"There are reasonable grounds to believe that limited quantities of toxic chemicals were used," the commission's four human rights experts said.
Both government forces and rebels have been accused of deploying such weapons, which are banned under international law.