INDIANAPOLIS - A new federal report says inmates at jails in Indianapolis, Baltimore, St. Louis and Philadelphia face the nation's highest levels of sexual abuse at the hands of guards.

The U.S. Department of Justice's report says the Marion County Jail in Indianapolis had the nation's highest rate of inmate sex abuse by staff. Its 7.7 percent abuse rate was well above the 1.8 percent average abuse rate among all jails based on inmate surveys from February 2011 to May 2012.

The Baltimore City Detention Center had the second-highest abuse rate by guards at 6.7 percent. The St. Louis Medium Security Institution and the Philadelphia City Industrial Correctional Center both had 6.3 percent abuse rates.

The report's authors surveyed inmates at 233 prisons, 358 local jails and 15 special correctional facilities.