RICHMOND, Va. — Atlanta Falcons quarterback Michael Vick formally pleaded guilty to a federal dogfighting charge yesterday and minutes later solemnly apologized to the NFL, his team and the youth of America.

His eyes moist and his voice barely audible, the suspended former Pro Bowler spoke without notes — "from the heart," he said — as animal rights activists and Vick supporters gathered outside a hotel near the federal courthouse.

"I want to apologize to all the young kids out there for my immature acts," he said. "If I'm more disappointed with myself than anything, it's because of all the young people, young kids that I've let down, who look at Michael Vick as a role model."

"Dogfighting," he added, "is a terrible thing."

A humbled Vick ran a gantlet of several dozen protesters as he entered the courthouse and quietly said "Yes, sir" and "No, sir" to U.S. District Judge Henry E. Hudson as he entered his plea to a single conspiracy count for running a brutal dogfighting ring with three co-conspirators.

Vick had admitted in court documents filed Friday that he was deeply involved in the venture and endorsed the killing of poorly performing dogs by hanging or drowning. He will be sentenced Dec. 10, and the judge in the case warned Vick that he is not bound by the 12- to 18-month prison sentence recommended by prosecutors and his attorneys.

After the hearing, Vick hugged his fiancee in the front row and wiped away a tear before heading to the hotel. He asked forgiveness from his teammates and the public. "I offer my deepest apologies to everyone," he said. "And I will redeem myself. I have to."

Vick said he had turned his life over to God and took responsibility for what he did.

"Not for one second will I sit right here and point the finger and try to blame anybody else for my actions or what I've done," Vick said. "I'm totally responsible."

It remains to be seen whether Vick's words and demeanor will sway Hudson, who told Vick: "The bottom line is that if I decide you deserve five years and give you five years, you can't appeal it. You're taking your chances here."

But Vick's statement — which was worked out with his attorneys, who deliberated into the night about where he would deliver it — was greeted with wary optimism by even some critics.

"I think time will tell if he is able to redeem himself from this horribly cruel crime," said Ann Chynoweth, director of the animal fighting and cruelty campaign of the Humane Society of the United States. "He said dogfighting is a terrible thing, so that is a start as far as being a positive role model goes."

Falcons owner Arthur Blank said he accepted Vick's apology. "My hope and my wish for Michael is that this is the beginning of a long journey," Blank said at a news conference in Atlanta. "This is not about Michael Vick the football player now. It's about Michael Vick the human being, the young man — a gifted young man who needs to refocus his life."

Left unclear yesterday was Vick's precise role in Bad Newz Kennels, the dogfighting venture that he started in 2001 with his co-conspirators and based on his property in Surry County, Va. Vick was not asked for specifics in the 20-minute court hearing, and he did not offer any in his public statement.

Linda Malone, a law professor at the College of William and Mary, said Vick had admitted enough to satisfy prosecutors but "is not going to volunteer any more factual details than necessary" because he could face additional state charges. A prosecutor in southeastern Virginia has said he is likely to seek indictments against Vick and his three co-defendants, who have also pleaded guilty to federal charges.

Absent any state charges or additional defendants in federal court, Friday's court papers would likely stand as the final public rendering of Vick's role, legal experts said. In those documents, Vick admitted that he agreed to the killing of six to eight dogs through the "collective efforts" of him and his co-conspirators. He did not admit to actually participating in the killing.

Vick also acknowledged that he provided most of the gambling money for fights that had purses in the thousands of dollars, but court documents do not say that he placed bets. They also do not indicate that he profited from the fights, saying instead that his co-conspirators pocketed winning purses.

Although Vick's ultimate sentence is unclear, U.S. Attorney Chuck Rosenberg said federal guidelines had appeared to call for a prison term of as long as six months and that a first-time offender like Vick might have received no jail time.

But because Vick's conduct was so "heinous, cruel and inhumane," Rosenberg said, prosecutors insisted that the sentencing range be adjusted upward to 12 to 18 months. Vick's attorneys agreed, an action Rosenberg called "highly unusual" for defense lawyers.

Staff writers Mike Wise and Mark Maske contributed to this report. Maske reported from Washington.