New Bombings in Syria as Obama Resists Bigger Role European Pressphoto Agency A man injured in an explosion in central Damascus on Tuesday was carried from the scene. BEIRUT, Lebanon - Deadly bombings hit the center of the Syrian capital, Damascus, and a major Syria border crossing into Turkey on Tuesday as President Obama strongly suggested that he would not be rushed into military entanglements in the Syria conflict over incomplete reports of chemical weapons use. The blasts in Syria, which killed at least 13 people in Damascus and at least five at the Bab al-Hawa crossing in northern Syria, came a day after an attempted assassination of Syria's prime minister in central Damascus from a bomb aimed at his motorcade. The prime minister, Wael Nader al-Halqi, survived the attack but at least five others including a bodyguard were killed, Syria's state news media reported. In a news conference in Washington, Mr. Obama said that despite an American intelligence assessment last week that there was evidence that chemical weapons had been used in Syria, the evidence had not yet surpassed his "red line" for a change of American strategy regarding the conflict, in which President Bashar al-Assad is fighting an increasingly violent insurgency. Mr. Obama said his previously stated position that the proven use of chemical munitions in Syria would be a "game changer" was not the position of the United States alone, and said there were still serious shortcomings in the intelligence. "What we now have is evidence that chemical weapons have been used inside of Syria, but we don't know how they were used, when they were used, who used them; we don't have chain of custody that establishes what exactly happened," Mr. Obama said. And when I am making decisions about America's national security and the potential for taking additional action in response to chemical weapon use, I've got to make sure I've got the facts. Mr. Obama also said that "if we end up rushing to judgment without hard, effective evidence, then we can find ourselves in the position where we can't mobilize the international community to support what we do." If investigations prove that the Syrian government had used chemical weapons in the conflict, Mr. Obama said, "we would have to rethink the range of options that are available to us." The United States is the largest donor of humanitarian assistance to civilians of the two-year-old Syrian conflict and has called on Mr. Assad to resign in a negotiated political transition. The Obama administration has furnished nonlethal aid to the insurgents but has resisted requests to arm them. Mr. Obama's remarks on Tuesday came against a backdrop of increasing pressure on the administration to be more precise about what would constitute the basis for an American intervention in Syria if chemical munitions were used. While some members of Congress have said the threshold for more active American involvement had been crossed, the administration has resisted. There also appears to be little American public appetite for a military engagement in Syria, according to a new New York Times/CBS News poll. The United Nations has authorized a 15-member panel of experts to travel to Syria to investigate the suspected chemical munitions use. Their trip has been stalled over a dispute with the Syrian government, which wants to limit the scope of their inquiry. At the United Nations on Tuesday, the Syrian ambassador, Bashar Jaafari, told a news conference that his government had been "cooperating intensively" on an investigation that would examine whether chemical weapons had been used in Khan al-Asal, near the northern city of Aleppo, on March 19. But he said that the United Nations had failed to provide sufficient evidence on suspected use in Homs and outside Damascus for the Syrian government to judge whether an inquiry into those incidents was merited. Britain and France have asserted that such evidence exists. The Syrian government has contended that rebels used a form of chlorine gas from a factory they had captured in Khan al-Asal, while the Syrian government is accused by its enemies of using sarin gas, a nerve agent known to have been stockpiled by Mr. Assad's military. Hania Mourtada reported from Beirut, and Rick Gladstone from New York. Reporting was contributed by Anne Barnard from Beirut, Sebnem Arsu from Istanbul and and Neil MacFarquhar from the United Nations.