"After careful deliberation, I have decided that the United States should take military action against Syrian regime targets," the president said in a statement made at the White House Rose Garden.

　　"This would not be an open-ended intervention. We would not put boots on the ground," he said, echoing a refrain repeated by his administration in the past days. "Instead, our action would be designed to be limited in duration and scope."

　　In a dramatic turnaround, the president said he would first seek authorization from Congress, as demanded by some lawmakers, before acting to punish Syria for its use of chemical weapons in an attack in the suburbs of Damascus, the Syrian capital, on Aug. 21.

　　"I will seek authorization for the use of force from the American people's representatives in Congress," he declared.

　　"We should have this debate," he said, with Vice President Joseph Biden standing at his side. "I respect the views of those who call for caution, particularly as our country emerges from a time of war that I was elected in part to end."

　　"The issue is too big for business as usual," he added.

　　Congressional leaders have agreed to debate and vote on the administration's action plan, as U.S. lawmakers will return to session on Sept. 9 after a summer break.

　　The United States has five cruise-missile equipped destroyers in the Mediterranean Sea, and press reports said U.S. military action will involve sea-launched cruise missiles or possibly long- range bombers.

　　In its efforts to build up the case, the White House on Friday released an unclassified U.S. intelligence report, which concluded with "high confidence" that Syrian government forces had used chemical weapons multiple times in the last year, and that the gas attack on Aug. 21 left at least 1,429 Syrians dead, among them 426 children.

　　Obama set a red line over the chemical weapons use a year ago, and he and his administration officials have vowed to hold accountable the Syrian government headed by President Bashar al- Assad in the past days.

　　"This attack is an assault on human dignity. It also presents a serious danger to our national security," Obama said in his Rose Garden statement. "It endangers our friends and our partners along Syria's borders. including Israel, Jordan, Turkey, Lebanon and Iraq."

　　Britain, however, dropped out of a possible coalition with the United States and France on Thursday as its parliament vetoed against a government action plan, dealing a severe blow to the Obama administration's momentum on Syria.

　　Moreover, an NBC News opinion poll released Friday show 50 percent of American voters oppose military intervention in Syria.