The Hague-based Organization for the Prohibition of Chemical Weapons said there had been a "spate of new allegations" of chlorine attacks in Syria, according to The Associated Press.
Syrian President Bashar al-Assad agreed to hand over 1,300 metric tons of chemical weapons and destroy production and storage facilities last year under a deal that averted threatened American military strikes, the AP reported.
The bulk of the chemicals have been destroyed on a U.S. ship and at commercial toxic waste processing facilities, according to the AP.
After coming under attack while doing fieldwork in Syria, where a civil war has killed more than 191,000 people, the team based its research on dozens of interviews with victims, physicians and witnesses, as well as video material, medical records and other evidence, but they did not say which side in the conflict had used chemical weapons in the battlefield, the AP reported.
Damascus still has to destroy 12 hangars and underground weapons facilities and clarify a series of discrepancies in the list of poisonous munitions it filed with the OPCW, the AP reported.
Even as some of the chemical weapons were being destroyed abroad, attacks with toxic agents were being reported in Syrian villages, leading to accusations from Western governments that Assad had not fully declared his arsenal, according to the AP.
Syria agreed to destroy its chemical weapons a year ago following global outrage over a sarin gas attack in Ghouta, a suburb of Damascus, in August 2013 that killed hundreds, the worst attack of its kind for quarter of a century, the AP reported.
The government and rebels blamed each other for that attack, but Western powers blame Assad and Russia says rebels were likely to have been responsible, according to the AP.