Syria warned of using chemical weapons by US, UK, France

Britain, France and the United States are warning Syria against using chemical weapons on opponents of the government. The foreign ministers of the three countries say in a joint statement that Syria's past use of such weapons "cannot be disputed."

They say they will "act strongly and swiftly" in the event of any future attack. The statement was released ahead of the two- and three year anniversaries of chemical weapons attacks in Syria for which the three nations vow to hold the perpetrators to account.

They also renewed demands for a negotiated political settlement to the conflict in Syria. The government of Syrian President Bashar Assad has denied using chemical weapons against opponents. International investigators have confirmed that the weapons have been used but stopped short of accusing specific perpetrators.