"When we have more information, that answer will become clear," he said when a reporter asked whether it was a matter of when, not if, the U.S. will take military action against Syria.
Hagel spoke at a news conference after meeting with his Malaysian counterpart, Hishamuddin bin Tun Hussein, on the first leg of a week-long trip to Southeast Asia.
Hagel was to give a policy speech on U.S. efforts to increase its focus and presence in the Asia-Pacific region later Sunday.
The Syria crisis illustrates the difficulty for Hagel, trying to spend more time in Asia and the Pacific even as security challenges continue to flare up across the Middle East. He participated Saturday in a White House meeting on Syria by a video teleconference link from Kuala Lumpur.
Asked about U.S. military options on Syria, Hagel spoke in broad terms about the factors President Barack Obama is weighing.
"There are risks and consequences for any option that would be used or not used for action or inaction," he told reporters. "You have to come to the central point of what would be the objective if you are to pursue an action or not pursue an action. So all those assessments are being made."
He said the administration is weighing many factors. These include an intelligence assessment of what some say appears to have been a chemical attack on civilians, as well as what he called legal issues and the matter of international support for any military response.