France's foreign minister has said western powers are preparing a tough response in case Syrian president Bashar Assad's regime deploys chemical or biological weapons in its civil war.
Laurent Fabius said "our response ... would be massive and blistering".
Mr Fabius, speaking on RMC radio, said: "We are discussing this notably with our American and English partners."
US president Barack Obama has said that if Mr Assad's regime were to use chemical or biological weapons, this would be a "red line" issue.
Mr Fabius said Russia and China are "of the same position", but acknowledged frustration at their continuing support for Mr Assad.
Syria's leadership has said it could use chemical or biological weapons if it was attacked from outside.
Syria is believed to have nerve agents as well as mustard gas and Scud missiles capable of delivering lethal chemicals.