A United Nations report released Monday confirmed that rockets loaded with sarin gas were used in an August 21 attack in Syria, although inspectors stopped short of saying who was responsible for the attack.
“Chemical weapons have been used in the ongoing conflict between the parties in the Syrian Arab Republic, also against civilians, including children, on a relatively large scale,” inspectors concluded in a 38-page report, which included analysis of chemical, environmental and medical samples.
Those samples provided “clear and convincing” evidence that rockets containing sarin were deployed in the area, the report said.
The inspectors spoke to more than 50 witnesses of the attack in a Damascus suburb, including survivors and first responders.
UN Secretary General Ban Ki-Moon told reporters after the release of the report that the results of the investigation are "overwhelming and indisputable," and he called the use of chemical weapons "a war crime."
But, he said, it is "for others to decide" whether to attempt to determine who perpetrated the attack.
"It was the team’s job to determine whether and to what extent chemical weapons were used – not who used them," he said. "It is for others to decide whether to pursue this matter further to determine responsibility. We may all have our own thoughts on this but I would just simply say that this was a grave crime and those responsible must be brought to justice as soon as possible."
Samantha Power, the US ambassador to the United Nations, said that the facts of the report underscore that only the Assad regime could have carried out the sarin attack.
"The technical details of the UN report make clear that only the regime could have carried out this large-scale chemical weapons attack," Power said.
While few have disputed that chemical weapons were used in the attack, the regime of Syria’s President Bashar Assad and opposition fighting against it have blamed each other for the use of the deadly gas.
But the United States has pointed blame squarely at the Assad regime, estimating that the attack killed over 1,400 people – including hundreds of children.
“In the days leading up to August 21st, we know that Assad's chemical weapons personnel prepared for an attack near an area where they mix sarin gas,” President Barack Obama said in an address to the nation on September 10. They distributed gasmasks to their troops. Then they fired rockets from a regime-controlled area into 11 neighborhoods that the regime has been trying to wipe clear of opposition forces.”
Secretary of State John Kerry announced on September 1 that hair and blood samples collected from the site by first responders tested positive for signatures of sarin gas, a man-made chemical warfare agent that interferes with nerve signals to the muscles.
“Bashar Assad now joins the list of Adolf Hitler and Saddam Hussein [who] have used these weapons in time of war," he said on NBC’s Meet the Press.
But Assad and his allies say that rebels are responsible.
President Vladmir Putin of Russia alleged in a New York Times op-ed published last week that rebel forces were responsible for the use of the chemical weapons.
“No one doubts that poison gas was used in Syria,” he wrote. “But there is every reason to believe it was used not by the Syrian Army, but by opposition forces, to provoke intervention by their powerful foreign patrons, who would be siding with the fundamentalists."
The report comes as Kerry tries to rally international support for the U.S.-Russian pact announced Saturday which would allow Syria’s stockpile of chemical weapons be removed or destroyed by next year.
Ban told reporters Monday that he has instructed the United Nations Security Council to act urgently to respond to the use of sarin.
"There must be accountability for the use of chemical weapons," he said. "Any use of chemical weapons by anyone, anywhere, is a crime."