BEIRUT — An international human rights group said Tuesday that evidence ‘‘strongly suggests’’ Syrian government forces fired rockets with warheads containing a nerve agent — most likely sarin — into a Damascus suburb last month, killing hundreds of people.
The report by Human Rights Watch was released as the international community weighs how to respond to the attack on Ghouta, which the United States, France, and others also have blamed on President Bashar Assad’s forces. The regime blames the rebels.
Human Rights Watch did not have direct access to the affected areas or the victims, but said its conclusions are based on witness accounts, the physical fragments of the weapons used, and the symptoms exhibited by victims and documented by medical staff.
The New York-based group said it sought technical advice from a specialist on the detection and effects of chemical warfare agents, and its analysts studied documented medical symptoms of the victims and videos posted on the Internet by activists after the attack.
‘‘This evidence strongly suggests that Syrian government troops launched rockets carrying chemical warheads into the Damascus suburbs that terrible morning,’’ said Peter Bouckaert, HRW’s emergencies director.
Symptoms of the victims from the attack ‘‘provide telltale evidence about the weapon systems used,’’ he added.
Three doctors who treated victims told the human rights organization that they exhibited a range of symptoms, including convulsions, frothing at the mouth, and dizziness — all of which are consistent with exposure to nerve agents such as sarin, they said.
The most toxic of the chemical compounds used as weapons, nerve agents affect the nervous system and are hazardous in both their liquid and gas states. They can be delivered in missiles, bombs, rockets, artillery shells, and other large munitions. The Syrian regime is believed to possess tabun, sarin, and VX.
Human Rights Watch added that evidence related to the type of rockets and launchers used in the attack ‘‘strongly suggests’’ weapon systems that are documented to be only in the possession of Syrian forces.
Syria’s main opposition bloc, the Syrian National Coalition, urged the West to go ahead with a strike against the regime.