Syria’s chemical weapons could be used at “a moment’s notice” and the international community should not accept any assurances from Syrian officials that they will not be used, US House Intelligence Committee Chairman Mike Rogers said on Wednesday.

US and other Western officials recently issued sharp warnings to Syrian President Bashar Assad not to deploy chemical weapons. Syria called those warnings a “pretext for intervention” in the civil war.

Rogers, a Republican, told Reuters in an interview that the Syrian government’s activities related to chemical weapons were a shift in posture and a major concern.

“I believe that they have put elements of their chemical weapons program in a condition of which they could be used at a moment’s notice, which is very different from before,” Rogers said.