Giffords was holding a constituent meeting at the grocery store in Tucson when the shooting occurred. She was shot in the head.
The Pima Countly Sheriff's Department is reporting 6 people are dead. Officials say among those killed is U.S. District Judge John Roll. The other victims are:
- Gabriel Zimmerman, 30, Giffords' director of community outreach and engaged to be married
- Dorwin Stoddard, 76, a pastor at a Tucson church
- Christina Greene, 9, a student at Mesa Verde Elementary who came to the event to learn more about the political process
- Dorthy Murray, 76
- Phyllis Scheck, 79
Five people, including Giffords, were listed in critical condition and five were in serious condition. All had come out of surgery by Saturday evening.
Giffords is now in the ICU unit. After performing surgery earlier in the day, doctors say they are "optimistic" about her recovery.
The suspected is identified as Jared Lee Loughner. Officials say Rep. Giffords was Loughner's intended target. Two people, including a member of Giffords' staff, are said to have tackled Loughner to keep him from getting away.
Pima County Sheriff Clarence Dupnik says investigators have a photo of another possible suspect in the shooting. However, officials say Loughner has claimed sole responsibility for the attack.
Federal agents are pouring over captured versions of a MySpace page that belonged to Jared Loughner and over Youtube video published to the Internet weeks ago under an account "Classitup10" and linked to him.
The MySpace page, which was removed within minutes of the gunman being identified by U.S. officials, included a mysterious "Goodbye friends" message published hours before the shooting and exhorted his friends to "Please don't be mad at me."
In one of several Youtube videos, which featured text against a dark background, Loughner described inventing a new U.S. currency and complained about the illiteracy rate among people living in Giffords' congressional district in Arizona.
"I know who's listening: Government Officials, and the People," Loughner wrote. "Nearly all the people, who don't know this accurate information of a new currency, aren't aware of mind control and brainwash methods. If I have my civil rights, then this message wouldn't have happen (sic)."
President Obama spoke to the nation late Saturday afternoon about the shooting. He called Giffords a friend and is hopeful she and the others will survive.
The president sent FBI Director Robert Muller to Arizona to support the investigation. Because a member of Congress was injured and a federal judge murdered, the federal government will lead the investigation and prosecution.
Speaker of the House John Boehner (R-OH) released the following statement. “I am horrified by the senseless attack on Congresswoman Gabrielle Giffords and members of her staff. An attack on one who serves is an attack on all who serve. Acts and threats of violence against public officials have no place in our society. Our prayers are with Congresswoman Giffords, her staff, all who were injured, and their families. This is a sad day for our country."
Giffords, a Democrat, had just begun her third term. The 40-year-old was re-elected in November, edging out a Tea Party candidate.
Giffords was first elected in 2006. She has served as chairwoman of the House Space and Aeronautics Subcommittee and also holds seats on the House Science and Technology and Armed Services committees. Her husband, astronaut Mark Kelly, flew to Tucson Saturday afternoon on a NASA jet to be with his wife. Kelly is scheduled to command the final mission of Endeavor in April.
The Associated Press, CBS News & the L.A. Times contributed to this report.