White House: US believes Syrian regime used chemical weapons - U.S. News

By Kristen Welker, Jim Miklaszewski, Courtney Kube and Tracy Connor, NBC News

The White House said Thursday that the U.S. believes "with some degree of varying confidence" the Syrian government has used chemical weapons — specifically the nerve agent sarin — against its own people.  

A letter from the White House to members of Congress said the assessment was based on "physiological samples" but called for a United Nations probe to corroborate it and nail down when and how they were used.  

"We are continuing to do further work to establish a definitive judgement as to whether or not the red line has been crossed and to inform our decision-making about what we'll do next," a White House official said.  "All options are on the table in terms of our response," the official added............  

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White House: US believes Syrian regime used chemical weapons - U.S. News