President Barack Obama has paid tribute at a memorial service in Arizona to the six people killed and 13 injured in Saturday's shooting in Tucson.

奥巴马总统向上周六图森市袭击案的6位死者以及13位受伤者致敬。

He said he could not "fill the hole" torn in US hearts, but urged the nation to honour the victims through unity¹.

He said lawmaker Gabrielle Giffords, who was hurt in the attack, had opened her eyes for the first time that night.

Suspected gunman Jared Loughner has been charged with several offences and could face the death penalty if guilty.

More than 14,000 people gathered for the service at the University of Arizona's basketball arena², the McKale Memorial Center, in Tucson.

"There is nothing I can say that will fill the sudden hole torn in your hearts," said Mr Obama.

"But at a time when our discourse³ has become so sharply polarized - at a time when we are far too eager to lay the blame for all that ails⁴ the world at the feet of those who think differently than we do - it's important for us to pause for a moment and make sure that we are talking with each other in a way that heals, not a way that wounds."

The president added that it was impossible to know "what might have stopped those shots from being fired or what thoughts lurked⁵（潜伏，埋伏） in the inner recesses⁶ of a violent man's mind".

Mr Obama then praised the bravery of those who stopped the gunman while he paused to reload.

"Heroism⁷ is here all around us, in the hearts of so many of our fellow citizens, just waiting to be summoned - as it was on Saturday morning," he said.

Speaking before the president, Arizona Governor Jan Brewer⁸ said: "We will go forward unbending and unbowed（不弯的，不屈服的） ."

"We know that the violence that occurred Saturday does not represent this community, this state or this country," said Homeland Security Secretary and former Arizona Governor Janet Napolitano.

The first stop for the president after arriving in Tucson was the hospital where Ms Giffords and others are being treated.

Ms Giffords, a Democrat⁹, remains¹⁰ critically ill after being shot through the head in the attack outside a grocery store where she was holding a constituency（选民） event.

Mr Obama spent 10 minutes with Ms Giffords and her husband, Mark Kelly, before meeting four others injured in the shooting, including two of Ms Giffords' staff members.

During his speech at the memorial service, the president said Ms Giffords had opened her eyes a few minutes after he left her room in the hospital, for the first time since she was hospitalised.

"Gabby opened her eyes. So I can tell you she knows we are here. She knows we love her. And she knows that we are rooting for（支持，赞助） her through what is undoubtedly¹¹ going to be a difficult journey," he said.

Former House Speaker Nancy Pelosi, Senator Kirsten Gillibrand and Representative Debbie Wasserman Schultz - all friends of Ms Giffords - were in the room when she opened her eyes.