The White House said on Friday it was continuing to study evidence that the Syrian government has used chemical weapons and would not set a timetable for corroborating reports.
"I'm not going to set a timeline, because the facts need to be what drives this investigation, not a deadline," White House spokesman Jay Carney told reporters at a briefing.
"We are continuing to work to build on the assessments made by the intelligence community, that the degrees of confidence here are varying, that this is not an airtight case," he said.
In response to a question, Carney said that President Barack Obama would consider a range of options including, but not exclusive to, military force, should it be determined that Syria has used chemical weapons.
"He retains all options to respond to that, all options," Carney said. "Often the discussion, when people mention all options are on the table, everyone just talks about military force. It's important to remember that there are options available to a commander in chief in a situation like this that include but are not exclusive to that option."
Reporting by Roberta Rampton and Mark Felsenthal; Editing by Vicki Allen and Sandra Maler