One angry attendee at the rally in College Park, Md., shouted "Obama you're a liar. Obama, your health care kills children. Abortion is murder."
The heckler drew boos from the supportive crowd and, as he was escorted out of the building by officials, some threw cups and crumpled bags at him.
Only pausing for a moment, the president asked, "What's going on?" and quickly picked up from where he left off. Watch the video at left.