President Obama said it was important for Americans to pause to make sure "we are talking with each other in a way that heals, not in a way that wounds."
The Obamas stand next to Giffords' intern, Daniel Hernandez, who was honored as a hero at the event. Arizona Gov. Jan Brewer said Hernandez's quick actions probably saved Giffords' life. Hernandez rushed to help the congresswoman after she was shot.
People wait in line for the memorial service at the University of Arizona campus in Tucson.
President Obama presides over a memorial service to pay tribute to the six people who were killed and the 14 wounded in the assassination attempt on congresswoman Gabrielle Giffords.
