Hagel, White House assess Syrian chemical weapons use


"What I won't do is speculate about how much time might be required to gather the evidence necessary to be able to assess clearly, in a way that has been corroborated and reviewed, whether or not this red line has been crossed," Carney said. "I think all Americans would hope and expect that on a matter this serious that we would be very careful in this process and insist that we gather all the facts."

Carney added that he did not "think it's possible" to set a timetable for the evaluation of the alleged Syrian chemical attack, noting that "it is not easy business."

Last week, administration officials said initial intelligence indicated it was likely that the nerve gas sarin had been used by the Assad regime. But the White House emphasized again Monday that that assessment, while grounded in "tangible" evidence, was held with "varying degrees of confidence." Carney repeatedly insisted that investigators needed to do more work before the U.S. responded, calling the intelligence reports "not sufficient."

"There is much more to be done to verify conclusively that the red line the president has talked about has been crossed," Carney said.

For more on Hagel and Carney's comments, click here.