The White House said on Thursday that American intelligence agencies now believed, with \u201cvarying degrees of confidence,\u201d\u009d that the Syrian government had used chemical weapons, but it said it needed conclusive proof before President Obama would take action.<\/p>\n
The disclosure, in letters to Congressional leaders, takes the administration a step closer to acknowledging that President Bashar al-Assad has crossed a red line established by Mr. Obama last summer, when he said the United States would take unspecified action against Syria if there was evidence that chemical weapons had been used in the civil war.<\/p>\n
The White House emphasized that, \u201cgiven the stakes involved,\u201d\u009d the United States still needed \u201ccredible and corroborated facts\u201d\u009d before deciding on a course of action. The letter, signed by the president\u2019s director of legislative affairs, Miguel E. Rodriguez, said the United States was pressing for a \u201ccomprehensive United Nations investigation that can credibly evaluate the evidence and establish what happened.\u201d\u009d<\/p>\n