US President Barack Obama vowed on Saturday that Syria will be held to account if it fails to live up to its promises to surrender chemical weapons as he faced questions about how a deal brokered by US and Russian diplomats would be enforced.In a statement, Obama said a framework deal was an important, concrete step toward getting Syria's chemical weapons under international control so they can ultimately be destroyed. The deal emerged from talks between US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov."While we have made important progress, much more work remains to be done," said Obama.Obama has been bombarded with criticism for his handling of Syria and a muddled message. First, he took US forces to the brink of a military strike over an Aug. 21 poison gas attack in Syria that Washington blames on Syrian President Bashar Assad. He then asked Congress to authorize it, but less than a week later requested lawmakers hold off on a vote to allow diplomacy more time.He now faces questions about how the Syrian diplomatic deal will be enforced, after senior administration officials said on Friday the United States will not insist that the use of military force be included among the consequences Syria would face in a UN Security Council resolution being negotiated."Absent the threat of force, it's unclear to me how Syrian compliance will be possible under the terms of any agreement," said Republican Senator Bob Corker of Tennessee.Obama, in his statement, insisted that the United States "remains prepared to act" should diplomatic efforts fail.The deal between the US and Russia to destroy Syria's chemical weapons will afford Assad months to "delay and deceive" while more die in that country's war, two senior Republican senators said on Saturday."It requires a willful suspension of disbelief to see this agreement as anything other than the start of a diplomatic blind alley, and the Obama administration is being led into it by Bashar Assad and (Russian President) Vladimir Putin," Senators John McCain of Arizona and Lindsay Graham of South Carolina said in a statement. Obama said the United States will continue working with Russia, the United Kingdom, France, the United Nations and others to "ensure that this process is verifiable, and that there are consequences should the Assad regime not comply with the framework agreed today.""In part because of the credible threat of US military force, we now have the opportunity to achieve our objectives through diplomacy," he added.US forces were still positioned for possible military strikes on Syria."We haven't made any changes to our force posture to this point," Pentagon spokesman George Little said in a statement Saturday. Obama, briefed on the results of the Geneva talks by his national security adviser, Susan Rice, said he had spoken to both Kerry and the US ambassador to the United Nations Samantha Power, who will lead US efforts on the UN negotiations.