A bomb explosion badly damaged the shrine over the grave of Saddam Hussein's father early on Tuesday, a police source said.
"Several explosive charges were planted around the small mosque shrine over the grave of Saddam's father in Tikrit cemetery, detonated at about 6:20 a.m. (0320 GMT)," the source from Tikrit police told Xinhua on condition of anonymity.
The grave was located on the edge of the cemetery near Saddam's home village of Awjah, 10 km east of Tikrit.
The bombing came just hours before trial of Saddam and seven of his co-defendants was due to resume after a two-week recess.
Saddam and his aides were facing charges over crimes against humanity, including the killing of over 140 Shiite men in a village north of Baghdad after a failed assassination attempt on Saddam in 1982.