France says it's certain that chemical weapons have been deployed in Syria.

The French Foreign Miniser says tests in Paris have detected the poisonous nerve gas Sarin from samples recovered from the country.

Laurent Fabius said there was no doubt the Syrian government had used Sarin - but he did not say when or where the nerve agent had been used.

The test results have now been handed over to the United Nations.

Meanwhile, the US says more work needed to be done to establish who was responsible for the use of sarin gas, the amount used and the circumstances in which the chemical weapon was used