UN experts will confirm in a report to be released next week that chemical weapons were used in an attack near Damascus, UN leader Ban Ki-moon predicted Friday.
"I believe the report will be an overwhelming report that the chemical weapons was used," said Ban who also launched a new outspoken attack on Syria's President Bashar al-Assad.
Ban also gave a UN estimate that 1,400 people were killed in an August 21 attack which led to western threats of a military strike on Assad's forces.
UN inspectors were in Syria to launch an investigation into the general use of chemical weapons in the country's 30-month-old conflict when the suspected sarin gas attack on Ghouta near Damascus took place.
The United States, Britain and France blame Assad's forces for the attack. The Syrian government, backed by Russia, say opposition rebels used the banned gas.
UN investigation leader Ake Sellstrom is expected to send his report to Ban on Monday. So far no details of his inquiry have been given. Sellstrom is not allowed to say in the report who carried out the attack.
Ban did not blame Assad's government for the Ghouta assault but said the Syrian leader has "carried out many crimes against humanity."
The UN leader insisted that there has to be "accountability" once the war is over.