A UN report expected next week will "overwhelmingly" confirm that chemical weapons were used in Syria last month.
UN secretary general Ban Ki-moon (pictured) made no comment on who was to blame for the attack in Damascus, as that is not part of the report's remit.
But he did say Syria's president Bashar al-Assad was guilty of "crimes against humanity".
The US and Russian foreign ministers are continuing their talks on a plan to make safe Syria's chemical weapons.
The UN Secretary General was clear about Assad's role in the deadly civil war.
