U.S. officials say intelligence indicates the regime of Syrian President Bashar al-Assad has used deadly chemical weapons in its conflict with rebel fighters. The announcement raises the prospect of more direct U.S. intervention in Syria since President Obama has referred to the use of such weapons as a “game changer.” But the White House says the current information is not conclusive enough to spur action. Defense Secretary Chuck Hagel described the findings Thursday.

Chuck Hagel: “The U.S. intelligence community assesses with some degree of varying confidence that the Syrian regime has used chemical weapons on a small scale in Syria, specifically the chemical agent sarin. We still have some uncertainties about what was used, what kind of chemical was used, where it was used, who used it.”

Hagel’s remarks came a day after he had rebuffed similar claims made by the Israeli government about chemical weapons use by the Syrian regime.