WASHINGTON (AP) — U.S. officials say the intelligence linking the Syrian President Bashar Assad or his inner circle to the alleged chemical weapons attack that killed at least 100 people is no "slam dunk."

The officials say questions remain about who controls some of Syria's chemical weapons stores, and there are doubts about whether Assad himself ordered such a strike.

President Barack Obama has declared unequivocally that the Syrian government is responsible and has been laying the groundwork for an expected U.S. military strike.

A report by the Office of the Director for National Intelligence builds a case that Assad's forces are most likely responsible but also points to gaps in the U.S. intelligence picture.

The intelligence officials spoke on condition of anonymity because they were not authorized to discuss the issue publicly.