A report by the group said patients had arrived in three facilities it supports in the Damascus governorate on August 21, when opposition activists claim chemical attacks were launched against rebels.
The report appears to be the most concrete information yet that chemical weapons were used.
“Medical staff working in these facilities provided detailed information to MSF doctors regarding large numbers of patients arriving with symptoms including convulsions, excess saliva, pinpoint pupils, blurred vision and respiratory distress,” said Dr Bart Janssens, MSF director of operations.
“MSF can neither scientifically confirm the cause of these symptoms nor establish who is responsible for the attack,” said Dr Janssens. “However, the reported symptoms of the patients, in addition to the epidemiological pattern of the events—characterised by the massive influx of patients in a short period of time, the origin of the patients, and the contamination of medical and first aid workers—strongly indicate mass exposure to a neurotoxic agent. This would constitute a violation of international humanitarian law, which absolutely prohibits the use of chemical and biological weapons.”
The US, under increasing international pressure to act, appears to be weighing its options in the wake of the alleged chemical attacks. Opposition groups claim that as many as 1,300 people were killed
US commanders have prepared a range of “options” for Mr Obama if he chooses to launch an attack on the Damascus regime, US Defence Secretary Chuck Hagel said earlier. Mr Obama has described the alleged attacks as “troublesome” and of “grave concern”. Britain has directly blamed the Assad regime.
But he declined to provide any details on the positioning of US troops and assets.
US officials are meeting at the White House today to discuss their options, including possible military action.
The Syrian government on Saturday said the rebel fighters had used chemical weapons, countering the charges that the Assad regime was behind the attacks.
State television ran footage of “barrels filled with highly dangerous toxic and chemical agents” as well as gas masks, saying they were only a small sample of what had been unearthed in overrunning rebel positions.
The rebels “used these agents to try to halt the advance of the army,” it said.
Iran, the chief regional ally of the Assad regime, also said there is “proof” rebels used chemical weapons.
The Syrian opposition has dismissed such claims.