WASHINGTON, Dec. 18 (Xinhua) -- Cases of brutality inflicted by U.S. police officers are on the rise, according to Justice Department statistics revealed by USA Today Tuesday.

    Cases in which police and other law enforcement authorities used excessive force or other tactics, violating victims' civil rights, have increased by 25 percent from 224 in the 2001 fiscal year to 281 in the fiscal year 2007, according to the statistics.

    Federal records also show the vast majority of police brutality cases referred by investigators are not prosecuted.

    The cases involve only a fraction of the estimated 800,000 police officers in the country, but they reflect concerns that reduced standards, training and promotion of less experienced officers into the higher ranks could undermine supervision of police conduct.

    For the past few years, dozens of police departments across the country have scrambled to fill vacancies.

    The recruiting effort, which often features cash bonuses, has intensified since 9/11, as many police recruits have been drawn to military service.