The Washington Post

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Seeking to a build a case for Congress's approval to use force against the Syrian government, US Secretary of State JohnKerry said on Sunday that tests proved positive for use of the sarin gas in Syrian chemical attacks last month.Kerry told NBC's Meet the Press that fresh laboratory tests of blood and hair samples obtained from emergency workers in Damascus tested positive for the gas demonstrating that it was used in the August 21 attack that killed more than 1400 people,reported.Kerry said that US officials had learned of the use of sarin only in the last day. This was the first time that a US official identified what type of gas was used in the attack, according to the report.“So this case is building and this case will build,” Kerry told NBC, adding, “I don’t believe that my former colleagues in the United States Senate and the House will turn their backs on all of our interests, on the credibility of our country, on the norm with respect to the enforcement of the prohibition against the use of chemical weapons.”Kerry voiced confidence on Sunday that Congress "will do what isright" with President Barack Obama 's request that it approve hiscall for limited US military strikes against Syria An unclassified US intelligence report released last week said US authorities have a high degree of confidence that the Syrian government of President Bashar Assad was responsible for the August 21 attack. It stated that this is the strongest position the US intelligence community that vetted the report can take short of confirmation.