Chemical weapons inspectors and United Nations staff investigating alleged use of chlorine gas in Syria came under attack on Tuesday, officials said.
The Organization for the Prohibition of Chemical Weapons said a convoy travelling to the site of an alleged chlorine-gas attack was targeted.
"All team members are safe and well and are travelling back to the operating base," it said in a statement.
The watchdog said last month Syria's government had agreed to let it send a team to investigate allegations of chlorine gas attacks and had said it would provide security in areas under its control.
OPCW's Director General Ahmet Uzumcu expressed concern over Tuesday's incident, stressing that security of the mission was paramount.
"Our inspectors are in Syria to establish the facts in relation to persistent allegations of chlorine gas attacks," he said. "Their safety is our primary concern, and it is imperative that all parties to the conflict grant them safe and secure access."
Rebels in Daria, near Damascus, say their town has been targeted by small barrel bombs that appeared to contain chlorine gas, and the U.S. said last month there were “indications” that a “toxic industrial chemical,” possibly chlorine, was used in Syria.
Chlorine has industrial uses but if used as a weapon is officially considered a chemical weapon under the Chemical Weapons Convention, an international arms agreement.