US Democratic Senator from Michigan US Congressman Sander Levin talks to reporters on Capitol Hill in Washington on September 1, 2013 after a closed members-only security briefing on Syria. Secretary of State John Kerry said Washington has proof the Syrian regime used sarin gas in a deadly Damascus attack, as he backed the US administration's call for Congress to approve military strikes. After President Barack Obama asked lawmakers Saturday to vote for punitive military action against the Syrian regime, Kerry warned the world cannot turn a blind eye to chemical weapons use.
