"The National Coalition totally rejects the lies from the (President Bashar al-) Assad regime and considers them a desperate bid to divert attention from its repeated crimes and methods against Syrian civilians," the main opposition bloc said.
The "international community knows full well that the Assad regime is the only party in Syria which possesses the means to produce, use and stock chemical weapons," the statement said.
It also said it was trying to obtain satellite imagery proving the regime's use of chemical weapons and criticised UN investigators for the delay in visiting the site of an alleged "massacre" Wednesday with such arms in a Damascus suburb.