A total of 28 people were killed and 55 others injured in separate shootings and bombings across Iraq, including a suicide tanker bomb attack on Saturday, police and medical sources said. In Salahudin province, seven security members were killed and some 20 others wounded around noon when a suicide bomber rammed his explosive-laden tanker into an army checkpoint and blew it up on a main road in south of the city of Dujail, some 60 km north of Baghdad, a provincial police source told Xinhua on condition of anonymity. The suicide bomber targeted the checkpoint while a convoy of police vehicles was passing, the source said. In a separate incident, three members of a government-backed Sahwa paramilitary group were killed by gunmen who attacked their checkpoint in the town of Dowr near Salahudin's provincial capital city of Tikrit, the source added. The Sahwa militia, also known as the Awakening Council or the Sons of Iraq, consists of armed groups including some powerful anti-U.S. Sunni insurgent groups, who turned their rifles against the al-Qaida network after the latter exercised indiscriminate killings against both Shiite and Sunni Muslim communities. Also in the province, a soldier was killed and three others were injured when a roadside bomb struck their car on a main road in south of Dowr, he said. Salahudin province is a Sunni-dominated province and its capital Tikrit, some 170 km north of Baghdad, is the hometown of former president Saddam Hussein. In Anbar province, 11 people were killed and 20 others wounded by artillery and mortar shelling on several neighborhoods in the militant-seized city of Fallujah, some 50 km west of the Iraqi capital of Baghdad, a medical source from the city hospital told Xinhua. In a separate incident, a civilian was killed and five of his family members were wounded when a roadside bomb went off near their car at a bridge in eastern the besieged-city of Fallujah, a provincial police source told Xinhua. The attack occurred while the family were fleeing the battles and the continuing bombardment on the city. The violence is part of ongoing operations by the Iraqi security forces to retake control of Fallujah that has been seized by militant groups for months, the source said. Alo in Anbar, soldier was killed and three others were wounded when two roadside bombs detonated near their patrol in the city of Rawa, some 250 km northwest of Baghdad, the source added. Anbar province has been the scene of fierce clashes that flared up after Iraqi police dismantled an anti-government protest site outside Ramadi in late December last year. In northern Iraq, two policemen were killed and four others were wounded in a roadside explosion near their patrol outside the city of Qaiyara in south of Nineveh's provincial capital city of Mosul, some 400 km north of Baghdad, a provincial police source anonymously told Xinhua. Separately, a policeman and a civilian were killed by gunmen in two incidents near Qaiyara, the source said.