Syrian government forces have used chemical weapons – probably nerve gas – in their fight against rebels waging a two-year-old uprising, the Israeli military’s top intelligence analyst said on Tuesday.

Brigadier-General Itai Brun told a security conference photos of victims showing foam coming out of their mouths and contracted pupils were signs deadly gas had been used.

“To the best of our understanding, there was use of lethal chemical weapons. Which chemical weapons? Probably Sarin,” Brigadier-General Itai Brun said in remarks broadcast on Army Radio.

The Syrian government and rebels last month accused each other of launching a chemical attack near the northern city of Aleppo.

On Monday, Defense Secretary Chuck Hagel, who is visiting Israel, said U.S. intelligence agencies were still assessing whether chemical weapons may have been used in Syria’s civil war.