Charles Barron, the fiery City Council member who made national news nearly four years ago when he said at a rally for slavery reparations that he would like to go up to the closest white person and say: “‘You can’t understand this, it’s a black thing,’ and then slap him, just for my mental health,” is off to an aggressive start in his run for Congress.

The upstart challenger to Rep. Edolphus Towns, a 12-year incumbent, is already going on the offensive.

“His time is up,” Mr. Barron said during a walk through his district earlier this week. “He’s simply been around too long and it’s not because of his age, because Nelson Mandela ran a country at 80. If you decide to retire on the job, don’t get mad at me because I want to see somebody come in here to fight.”

Mr. Barron, who was briefly a candidate for mayor last year, called Mr. Towns’ voting record a “national disaster” and said the congressman has been “missing in action” on dozens of issues.

Such harsh comments are no surprise from Mr. Barron, a former Black Panther. His tenure in city government has been peppered with provocative words and deeds, such as bringing Zimbabwe’s President Mugabe, an accused human rights violator, to City Hall and publicly criticizing Thomas Jefferson a “slave owning pedophile.”

Mr. Barron is one of three African American Democrats who have said they plan to challenge Mr. Towns, who is also black. The others are Assemblyman Roger Green, who pleaded guilty to three counts related to charges that he took free rides then got reimbursed by the state but later won his seat back, and the founder of a non-profit group called HipHop Speaks, Kevin Powell.

While Mr. Barron is popular in his council district – the 42nd, which includes East New York and Brownsville, two of the poorest neighborhoods in the city – the congressional district he is running for stretches into gentrifying Fort Greene and parts of Brooklyn Heights. Some political analysts say that Mr. Barron’s brief run for mayor last year, which got support from Rev. Al Sharpton, was his way of increasing his credibility for this race. Others point out that his divisive comments and actions may not play well on a larger stage.

Mr. Barron is undeterred. During a sit-down conversation in his district office, decorated with African tapestries, he said he thinks President Bush is “racist” for neglecting Katrina victims in favor of the Iraq war, said that black people should form their own political party, declared that Republican black politicians like Condoleezza Rice and Colin Powell are “enemies to world peace,” and remarked that it was time to “get over” the notorious comments he made at the 2002 rally.

“I verbally slapped white people,” he said. “They lynched us, hung us, stuck something up Abner Louima’s rectum, shot us 41 times. I verbally slapped them. Get over it. It was a rally comment that nobody cares about but the media.”

His take-no-prisoners style is tempered by his sense of humor and personal ease around even those he disagrees with. The Republican minority leader in the council, James Oddo, said despite “the rhetoric that makes you want to pull your hair out he continues to be on the top of my list for council member that I want to have a conversation with.” Mr. Oddo also called him intelligent, charming, and entertaining.

The other day, Messrs. Towns and Barron sat two seats apart in the front row of a middle school auditorium for a black history performance. After the performance, Mr. Towns, who is 71, defended his record against Mr. Barron’s attacks, saying he has secured more money in Urban Development Action Grant than any other district in the nation, helped revive downtown Brooklyn, and worked tirelessly on behalf of his constituents.

“They are going to look really ridiculous because I have been an effective member of the United States Congress,” he said. “I’ll be running on my record.”

Mr. Towns has recently taken some heat from labor unions and from his challengers for supporting the Central America Free Trade Agreement. While supporters believe it makes cheaper goods accessible, opponents say the district, which already has high unemployment, will lose jobs should the trade agreement pass.

Rep. Charles Rangel, who has served with Mr. Towns in Congress for years, said he didn’t think any of those who have said they will challenge Mr. Towns would actually do so. “They are testing the waters, which we all do, and when they see the waters are not warm I don’t think they are going to be candidates. Ed Towns has nothing to worry about.”

A political consultant, Bill Lynch, who is friendly with all the candidates, said Mr. Towns will have a substantial amount of money. “The verdict is still out” on how Mr. Barron will do in the western and southern part of the district, which includes Crown Heights and Brooklyn Heights, said Mr. Lynch. He also said Messrs. Barron and Green could take votes away from one another.

But Mr. Barron, who dropped out of the mayoral race after raising only $49,000, said he would raise between $300,000 and $500,000 and would stay in it until the end. “If there is a candidate who can beat Towns it’s me.”