Three people were killed and 20 others wounded in separate bombings and shootings in Iraq on Sunday, police said. A roadside bomb went off at a popular market in Nahrawan area in the southeastern the Iraqi capital of Baghdad, killing a civilian and wounding nine others, a police source told Xinhua on condition of anonymity. In a separate incident, a civilian was killed and seven others were wounded when a roadside bomb ripped through Abu Ghraib area, some 25 km west of Baghdad, the source said. In northern central Iraq, gunmen shot dead a Sunni tribal leader, who is also a leader of the government-backed Sahwa paramilitary group in Himreen area, some 40 km northeast of Salahudin's provincial capital city of Tikrit, which is about 170 km north of Baghdad, a provincial police source anonymously told Xinhua. 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. In addition, four policemen were wounded in a roadside bomb explosion near their patrol near the city of Tuz-Khurmato, some 90 km east of Tikrit, the source said. Meanwhile, Iraqi security forces backed helicopters carried out a large-scale offensive in the vast desert which stretches through Iraq's western province of Anbar to the borders with Syria, Jordan and Saudi Arabia, in an attempt to hunt down al-Qaida militants. Al-Qaida militants are believed to be responsible for blowing up a booby-trapped shelter on Saturday in the desert area of Wadi Houran near the city of Rutba, some 370 km west of the Iraqi capital of Baghdad, killing up to 15 soldiers, Major General Mohammed al-Karwi, commander of the Iraqi Army 7th Division, commander of its 28th Brigade and three other senior officers. Iraq is witnessing its worst violence in recent years. According to the UN Assistance Mission for Iraq, 8,109 Iraqis, including 952 members of Iraqi security forces, were killed in the country from January to November this year.