The Obama administration notified Congress Thursday that the U.S. intelligence community has newly assessed that Syria probably used chemical weapons, but cautioned that further tests are necessary and said it is pressing for the United Nations to conduct a comprehensive investigation.

“Our intelligence community does assess with varying degrees of confidence that the Syrian regime has used chemical weapons on a small scale in Syria, specifically the chemical agent sarin,” the White House said in a letter to Congress Thursday.

The new assessment, announced by Defense Secretary Chuck Hagel in the United Arab Emirates Thursday, was finalized in the past twenty four hours and received with evident reluctance by the Obama administration, which has expressed strong misgivings about the prospect of deeper entanglement in a new Middle Eastern conflict.

But the administration decided to publicly release the findings, which were contained in an assessment requested by some members of Congress, as several allied governments and foreign officials, including in Israel, the UK and Qatar, have made similar claims, to press for a comprehensive probe.

The US intelligence assessment “is based in part on physiological samples,” the White House letter said. But it cautioned that “the chain of custody” of the physiological samples it tested “is not clear, so we cannot confirm how the exposure occurred and under what conditions.” Blood samples and soil samples are the type of physiological material that would be tested for chemicals, a western diplomat said Thursday.

“Precisely because the President takes this issue so seriously, we have an obligation to fully investigate any and all evidence of chemical weapons use within Syria,” the White House letter said.

“Given the stakes involved, and what we have learned from our own recent experience, intelligence assessments alone are not sufficient,” the White House letter said, obliquely referring to past flawed US intelligence assessments that Iraq had WMD. Only “credible and corroborated” facts will guide US decision-making, it continued.

It’s important that any evidence be “air-tight,” a senior US official later echoed in a press call.

The White House said it was consulting closely with allies, particularly the UK and France, in considering possible next steps. Vice President Joe Biden was also meeting with Jordan’s King Abdullah on Thursday. Hagel announced last week that the US was sending an additional 200 US troops there.

Earlier Thursday, a French official said the French government did not have conclusive evidence of the use of chemical weapons in Syria, but had strong concerns, and was also pressing for a broader UN probe.

“France does not have proof of the use of chemical weapons at this stage, but France is actively investigating with its partners,” the French official, speaking not for attribution, told journalists. Continue reading →