DES MOINES - With tactical officers dressed in black and armed with M4 assault rifles standing watch about 400 inmates have moved from downtown Des Moines jails to a new $68 million Polk County Jail.

The handcuffed prisoners became the brand new facility's first residents.

The initial group began boarding school buses shortly before 8 a.m. on Saturday for a six-mile trip to the new jail, which is near the northeast interchange of Interstate Highways 35/80 and 235.

Lt. Greg Peterman of the Polk County sheriff's department says the move has been planned for a long time.

The facility is initially expected to house about 930 prisoners, but it has room for 1,500 inmates - more capacity than any of Iowa's prisons, including the Iowa State Penitentiary at Fort Madison.