The unprecedented spike in complaints against police detailed in an independent report today highlights Police Commissioner Raymond Kelly’s final frontier as he seeks to secure his legacy: community relations.

That is the final item on the list of “Three C’s” Mr. Kelly often mentions when he talks about his policing strategy; the others are crime and counterterrorism. But with his success nearly unquestioned on the first two, Mr. Kelly lately appears to be focusing on shoring up the third, one of the more difficult tasks he faces in his remaining tenure.

Policing experts have pointed to increasing friction between the police department and minority communities on the heels of two police shootings and a number of arrests that have outraged local black leaders.

A report from the Civilian Complaint Review Board today shows that the number of citizen complaints of police misconduct increased by nearly 1,000, to 7,669, between 2005 and 2006. According to CCRB data obtained by The New York Sun, the precincts with the highest proportion of complaints per officer are in primarily black areas: Jamaica in Queens, Morris Heights in the Bronx, and Crown Heights in Brooklyn, where last week police allegedly assaulted a prominent black attorney.

A police spokesman, Deputy Commissioner Paul Browne, said the increase in complaints corresponds with a 26% jump in the use of the city’s 311 hotline to file complaints. He noted that the report shows that only 2.7% of the complaints were substantiated, the lowest in a decade, and that substantiated allegations involving force were down 61% from 2002, the year Mr. Kelly assumed command.

Still, the president of the Citizens Crime Commission, Richard Aborn, said he has gathered anecdotal evidence of rising tensions.

“The issue for the NYPD is do they agree with that?” he said. “If so, what can the department do to get out in front of the problem before it becomes a crisis?”

Whether he agrees or not, Mr. Kelly’s response to recent concerns has been aggressive.

“He is concerned about his legacy,” a John Jay College of Criminal Justice scholar, Eugene O’Donnell, said. “He knows that public safety and the confidence of people in the police go together.”

While Mr. Kelly has steadfastly defended his officers’ conduct, including the arrests of 30 black teenagers on their way to the funeral of an alleged gang member, he has also made moves that seem calculated to win over some critics.

Last week, he adopted one of the demands of Nicole Paultre-Bell — the fiancée of Sean Bell, an unarmed man killed in a hail of police gunfire last fall — when he announced that police officers who shot someone would have to undergo a blood alcohol test.

A few days later, he unveiled a new multicultural training initiative.

Some policing experts say Mr. Kelly’s response shows his adeptness at managing the tricky task, faced by all police commissioners, of balancing loyalty to his troops with his political role as the face of the NYPD.

“The way you respond to a bump is not to shut out the world, but to engage the world,” a political consultant, Bob Liff, said.

Yet a policing expert at the Manhattan Institute, Heather Mac Donald, warned that attempts to please the community could lead down a slippery slope.

“The core of New York policing has to be laser-sharp attention paid to crime prevention,” she said.

Mr. Aborn said the efforts made so far are a good first step. The next one, he suggested, should be adding a fourth “C”: counting. The Citizens Crime Commission is about to launch a citywide survey to measure the state of police-community relations.

“It’s not just about understanding cultural differences,” he said. “Maybe the police department needs to develop a way to more accurately measure the relationship between the police and the community.”