At least 18 people have been killed and 37 others injured in a series of bombings and shootings across Iraq, security officials say.Many of the victims of Tuesday attacks are reported to be members of the security forces. In the deadliest attack, seven people were killed and 26 others were wounded after a bomb exploded on a minibus in Baghdad’s Shia neighborhood of Sadr City. Four people, among them two police, were also killed in a car bomb explosion in Tarmiyah, north of Baghdad. Eight people were also injured in the attack. In another development, four Iraqi policemen were killed in clashes in the northern city of Mosul, while a senior police intelligence officer was killed and three police were wounded in a bombing near the city. In a separate incident, gunmen killed two anti-al-Qaeda militiamen near Tikrit, north of Baghdad. The attacks come a day after almost 70 people were killed in bomb attacks in the Iraqi capital, Baghdad. Nearly 500 people have been killed across Iraq since the start of May. On May 21, at least 42 people were killed and many others injured in a series of terrorist attacks across Iraq. A day earlier, nearly 100 people were killed in multiple attacks. The Iraqi Premier Nouri al-Maliki has blamed militant groups and the remnants of the former Ba’athist regime for the recent wave of violence. He has also accused some regional countries of fueling the violence in his country in a bid to topple the Iraqi government.