Obama to Syria: Using chemical weapons 'unacceptable'

US President Barack Obama has said use of chemical weapons by Syria's regime would be "totally unacceptable", saying there "will be consequences" if Bashar al-Assad chooses to deploy them.

Speaking at the National Defense Museum in Washington, DC, Mr Obama said: "We simply cannot allow the 21st Century to be darkened by the worst weapons of the 20th Century."

On Monday, the US said it feared Syrian President Assad might resort to using chemical weapons against his people. Meanwhile, the United Nations said it would withdraw all non-essential staff out of the country.