WASHINGTON - Slowly, with a sense of purpose, Rep. Gabrielle Giffords entered the House chamber Monday night to cast her first vote since she was shot in the head last January, a dramatic return that surprised colleagues. The chamber erupted in loud, sustained applause as Democrats enveloped Giffords with hugs and kisses.

Only minutes remained on a historic vote on the debt-limit bill. Most lawmakers were staring at the vote board when Giffords made her way through the door on the right side of the chamber. Few knew in advance that she would appear.

Democrats crowded around her as she mouthed "thank-yous." She used one hand to greet some, the other by her side. Her hair was dark and closely cropped, and she wore glasses. Her image was quite different from the one Americans saw seven months ago when she was sworn-in by House Speaker John Boehner, R-Ohio.

In the House chamber, colleagues, stunned and joyful, made their way to greet Giffords.

"It means so much to our country ... to witness the return of our colleague who is the personification of courage, of sincerity, of admiration throughout the country," Democratic leader Nancy Pelosi of California told the House.

Her return is "a triumph of the first magnitude and we are all so very proud of her," said Rep. Trent Franks, R-Ariz.

Giffords cast her vote - "yes" - and left the House chamber and the Capitol.

"I have closely followed the debate over our debt ceiling and have been deeply disappointed at what's going on in Washington," Giffords said in a statement release later.

"I strongly believe that crossing the aisle for the good of the American people is more important than party politics. I had to be here for this vote. I could not take the chance that my absence could crash our economy," she said.

The congressional news release was the only thing typical in a highly atypical moment.

Near the doorway to the House, Vice President Joe Biden greeted Giffords and marveled at her return.

"She's remarkable. Will matters," Biden said in an interview. "She's the embodiment of a strong, strong, strong woman. Think about what that woman's been through, and think about her determination."

On Jan. 8, Giffords, D-Ariz., was shot in the head in the parking lot of a Tucson grocery store while meeting with constituents. Six people were killed and 13 others, including Giffords, were wounded.

As Biden hugged Giffords, Republican presidential candidate Rep. Michele Bachmann, R-Minn., joined them.

"Sure, I like Michele Bachmann. We're all standing there and Michele walks up to see Gabby, because she cares about her," Biden said.

Giffords exited the House chamber by the east door, leaning heavily on an aide as she walked with obvious difficulty. Her husband, astronaut Mark Kelly, accompanied her. Police had cleared a path through a mob of reporters, and Giffords did not respond to questions and greetings.

Pelosi said Giffords had decided to come for the debt-ceiling vote, something the California congresswoman didn't learn about until Monday morning. The House's No. 2 Democrat, Steny Hoyer, learned about Giffords' return just 30 minute before she arrived.

After Giffords entered the chamber, Pelosi said, "we were just hugging. Girl hugs."

"It was one of the most thrilling moments for all of us to see this real heroine return to the House," Pelosi said, "and to do so at such a dramatic time."

Rep. Debbie Wasserman Schultz, D-Fla., a friend of Giffords, said she found out that the congresswoman would cast her vote from a 2 a.m. text message she received from Kelly.

"It's an incredibly important vote, pivotal for the country. And she felt it was really important that she be here to represent her district," said Wasserman Schultz, who added that Giffords had been reviewing the legislation.

"She still has rehabilitation to go through and a lot of recovery. So she's not ready to come back full time. But she wanted her district to have its voice here on probably the most important vote we'll cast this Congress," Wasserman Schultz said.

Giffords' political future remains uncertain. She has not filed for re-election next year though she has money for another bid, thanks to friends and colleagues who want to ensure she has the resources necessary. Documents filed with the Federal Election Commission last month show the Arizona Democrat had more than $787,000 in the bank at the end of June.

In Tucson on Monday, Pam Simon, a Giffords staffer who also survived the shooting, said she and everyone in her office huddled around the TV to watch the congresswoman's return to the floor.

"We were glued to it," she said. "We were hugging and some of us were in tears and some people were shouting. It was very joyful."

As a fellow survivor, Simon said she was "absolutely thrilled."

"I felt extremely emotional," she said. "It's a landmark. It signifies how far we've all come.

"We will be forever tied to that tragic event," she added. "Seeing Gabby there is just a wonderful step for us all."

She said she thought Giffords looked excited yet relaxed.

"Knowing Gabby, I know she is just so happy to be back among her colleagues," she said. "Didn't she look right at home?"

Sen. Kirsten Gillibrand, D-N.Y., a friend of Giffords, said in a statement that she had "tears of joy seeing Gabby on the floor tonight where she belongs."

"Gabby is a fighter and I always knew this day would come. She continues to inspire the nation with her strength and courage," Gillibrand said.

Giffords has been undergoing outpatient therapy in Houston since her release from the hospital in June.

Shortly after her appearance, a tweet appeared on Giffords' Twitter account: "The Capitol looks beautiful and I am honored to be at work tonight."

The man charged in the shooting, Jared Lee Loughner, has pleaded not guilty to 49 charges. Loughner was sent to a federal prison facility in Springfield, Mo., after a federal judge concluded he was mentally incompetent to stand trial.

Ron Barber, another Giffords staffer who survived the shooting, said he was in physical therapy for a gunshot wound to the thigh when she voted but that he tuned in when returned to his Tucson home.

"I have to admit I wept," Barber said. "All of us who were with her that day are encouraged by her progress."

Associated Press writers Charles Babington and Alan Fram in Washington and Amanda Lee Myers in Phoenix contributed to this report.