The French government said Tuesday that it has confirmed the use of sarin gas by the Syrian government, and a U.N. panel reported that it has "reasonable grounds" to believe chemical weapons have been used in the country's civil war, deepening international suspicions that the "red line" set by U.S. President Barack Obama has been breached.

France "now is certain that sarin gas was used in Syria multiple times and in a localized way" after tests carried out by a French laboratory on samples taken from victims proved the presence of the nerve gas, according to a statement issued by French Foreign Minister Laurent Fabius.

The report by the United Nations' independent commission of inquiry on Syria said the panel had not been able to ascertain which chemicals had been used, how they were delivered or by whom, because it did not have access to samples taken directly from victims.