AIDS demonstrators disrupted a Republican youth gathering on the floor of the party convention Wednesday, shortly after President Bush's twin daughters left the stage.

The incident occurred after Jenna and Barbara Bush introduced White House chief of staff Andrew Card (search). As he began speaking, about 10 protesters sitting in the crowd jumped up, blew whistles and began to chant, "Bush kills" and "Bush lies."

Card tried to continue speaking, but was drowned out and stopped as young participants in the morning event scuffled with the demonstrators. Police moved in to remove the protesters, including a young woman hoisted out by two officers — one at her shoulders and one at her knees

At least one GOP supporter was slightly injured. Daniel Suhr, 20, of Milwaukee, said he was punched in the head by a protester. He had a cut near his temple and the side of his face was reddened.

The AIDS activist group ACT UP later claimed responsibility. Police said there was at least one arrest.

Before the incident, the Bush daughters drew warm applause as they returned to the podium they had occupied Tuesday night, when they introduced their mother.

The 22-year-olds, dressed in tight jeans and heels, cracked a few jokes Wednesday, but did not repeat some of their cheekiest lines from Tuesday night's appearance.

"All joking aside, it really was a pleasure to introduce someone we love so much," Jenna Bush said.

The president's rambunctious daughters had their longest moment yet in the public spotlight Tuesday night. The Bush campaign earlier had said the young women would not follow Alexandra and Vanessa Kerry's lead by addressing the party convention.

"Jenna and I are really not very political, but we love our dad too much to stand back and watch from the sidelines," Barbara Bush said. "We realized that this would be his last campaign, and we wanted to be a part of it. Besides, since we've graduated from college, we're looking around for something to do for the next few years. Kind of like dad."

First lady Laura Bush followed her daughters at the podium, and gave delegates a personal glimpse of Bush's hard choices since Sept. 11 as well as his lighter side.

"I am enjoying this campaign. It has reminded me of our very first one, 26 years ago," when they were newlyweds and George W. Bush drove miles and miles in an Oldsmobile, campaigning for Congress, Mrs. Bush said.

"You learn a lot about your husband when you spend that much time in a car with him. By the end of the campaign, he had even convinced me to vote for him," she said. "This time I don't need any convincing."

The president himself was another surprise addition to the convention lineup. He thanked his daughters and introduced his wife by satellite from a campaign appearance in Pennsylvania.

"You make me so very proud," Bush said.

The girls, just graduated from Yale and the University of Texas, referred to high jinks that sometimes landed them in the newspaper headlines.

"We spent the last four years trying to stay out of the spotlight," Jenna Bush said to laughter from the delegates. "Sometimes we did a little better job than others."

She said they told their father they were "young and irresponsible," just the phrase he has applied to himself in a phase of youthful drinking.