Brigadier-General Itai Brun made the comments at a Tel Aviv security conference a day after U.S. Defense Secretary Chuck Hagel said on a visit to Israel that U.S. intelligence agencies were still assessing whether such weapons had been employed.

U.S. President Barack Obama has called the use of chemical weapons a “red line” for the United States that would trigger unspecified U.S. action.

“To the best of our understanding, there was use of lethal chemical weapons. Which chemical weapons? Probably sarin,” Brun said in the most definitive Israeli statement on the issue to date.

Photos of victims showing foam coming out of their mouths and contracted pupils were signs deadly gas had been used, he said.