15 killed in suicide blast targeting Baghdad police academy February 19, 2012 -- Updated 1301 GMT (2101 HKT) NEW: Seven people are killed in Diyala province Awakening council members are among the dead A suicide bomber targets the main entrance of a Baghdad police academy The bomber kills at least 15 people, police say Baghdad (CNN) -- Violent overnight attacks in Iraq killed nearly two dozen people Sunday. A suicide car bomber detonated at the main entrance of the police academy in eastern Baghdad, killing at least 15 people, Iraqi police officials said. The attack, which occurred at the traditional start of the work week in the Arab world, wounded at least 21 others, police officials said. The Baghdad police academy is the only one in the capital and is within the compound of the heavily -guarded interior ministry, but has a separate entrance. North of Baghdad, in Diyala province, seven others were killed in two attacks. In the first incident, four people were gunned down at a house late Saturday night. Three others were shot dead by gunmen who opened fire at a checkpoint just south of Baquba, the provincial capital. Among the victims were members of awakening councils -- groups mainly made up of Sunni Arab fighters who turned against al Qaeda. The U.S.-backed movement is credited for helping reduce violence, though council members have become targets for militants. The latest attacks come as Iraq remains mired in a political crisis split along sectarian lines, which has raised fears about a return to the levels of violence that nearly tore the country apart in 2005 and 2006. The bloodshed has also generated uncertainty about the ability of Iraqi security forces to ensure order, particularly after the United States withdrew troops at the end of 2011, as well as fear about the future.