Sen. Joe Biden expressed regret Saturday for describing presidential rival Barack Obama as an articulate and clean African-American, trying to stem damage to his nascent 2008 campaign.

"So, how was your week?" Biden, D-Del., said as he took the podium at the Democratic National Committee's winter meeting. He broke into a wide smile and then a chuckle as audience members laughed. Then he turned serious.

"I want to say that I truly regret that the words I spoke offended people that I admire very much," Biden said. He said he was grateful for the chance to be judged by his story and to be heard in the presidential race.

Biden spent his first day as an official presidential candidate Wednesday explaining his statement that Obama is "the first mainstream African-American who is articulate and bright and clean."

Biden is one of nine candidates in the Democratic presidential race. All appeared for the first time at the same event this weekend for the DNC gathering, and the divisions began to show, particularly on the Iraq war.

Former Iowa Gov. Tom Vilsack criticized senators in the race who refuse to cut the money that is paying for troops in Iraq. He did not name them, but front-runners Obama and Clinton are advocating a cap to the number of troops and their eventual withdrawal.

"The reality of capping troops or reducing the number of troops at some point in the future is not real change," Vilsack said.

"We cannot wait for the president or the Congress to make a political calculation as to when or how this is happening," Vilsack said, positioning himself as the Washington outsider in the race. "It is time for us to clearly say the war must end and our troops must be brought home now. Let me say that I think Congress has a constitutional responsibility and a moral obligation to do it now. Not a cap, an end. Not eventually, immediately."

The meeting is an unofficial kickoff the presidential campaign, with the candidates vying to capture the hearts and minds of the party faithful. Former Vermont Gov. Howard Dean, now the party leader, did so four years ago by borrowing the late Sen. Paul Wellstone's rally cry, "I'm from the Democratic wing of the Democratic Party."

Candidates encourage their supporters to come and provide cheering sections for their speeches. Campaign volunteers man tables outside the ballroom with buttons, posters, videos and freebies such as Hillary Clinton for president water bottles and bags of Vilsack popcorn.

Saturday's crowd was less than half of the thousands who packed the ballroom Friday to hear from front-runners Clinton, the New York senator; Obama, the Illinois senator; and 2004 vice presidential nominee John Edwards. Also speaking were Sen. Chris Dodd of Connecticut, former Gen. Wesley Clark and Rep. Dennis Kucinich of Ohio.

Saturday's lineup also included former Alaska Sen. Mike Gravel and New Mexico Gov. Bill Richardson.

"Maybe I'm not up there in all these polls, but you are the deciders, not the man in the White House," Richardson said. He repeatedly brought the crowd to its feet with his call to end the Iraq war by the end of the year and for a clean Democratic primary without any attacks. "I say to you today, stay loose. We've got a year to go."

Gravel is a virtual unknown who last served in elective office during the Carter administration. He used his speech chiefly to criticize other presidential candidates who voted for the resolution authorizing war in Iraq.

All the candidates tend to go over their allotted seven minutes, ignoring a timekeeper in the front row who held up a sign to tell them their time is up. Gravel, capitalizing on his rare chance to be heard before such an influential crowd, was the worst offender at 25 minutes.

Biden appeared to be trying to clean up his reputation as being exceedingly longwinded as well as his unfortunate remark about Obama. His speech came in under 12 minutes — longer than allowed, but the shortest of any of his rivals.