SAN FRANCISCO — The United States Department of Justice on Wednesday criticized this city’s Police Department for bias against African-American residents in its use of force and during traffic stops but stopped short of saying it was the result of racism.

Ronald Davis, the director of the Justice Department’s Office of Community Oriented Policing Services, said there were “significant deficiencies” in policing by the department here, including a 24 percent higher chance that African-Americans were pulled over by the police given the estimated number of black drivers in the city.

But Mr. Davis painted a nuanced picture of the bias and said there were many “unanswered questions.”

“We are not saying this is a result of any racial animus,” he said.

The report, for example, found that when minority officers only were involved in the use of force, “the severity of force used and the injuries sustained by community members increased.”