20 people were killed and 38 others wounded in separate violent attacks across Iraq, including an attack on polling center, police and medical sources said on Tuesday. In northern Iraq, militants wearing military uniforms carried out an attack late on Monday night on a balloting center at a village near the town of Daqouq near the city of Kirkuk, a local police source told Xinhua on condition of anonymity. The attackers were supposed to carry out search in the center, and they opened fire on the guards and some civilians, leaving three soldiers and seven people killed and wounded four soldiers and two civilians, the source said. In Anbar province, six civilians were killed and five others wounded by mortar barrage in the morning on several neighborhoods in the besieged city of Fallujah, a medical source from the city hospital told Xinhua. In a separate incident, gunmen attacked an army base near the town of Garma, just east of Fallujah, and killed a soldier and wounded two, along with destroying a military vehicle, a provincial police source anonymously told Xinhua. In the same area, gunmen fired mortar rounds on a convoy of army vehicles, leaving three soldiers killed and destroying several vehicles, the source said. Also in the province, chief of al-Khaldiyah police station and two of his guards were wounded when three roadside bombs went off in a quick succession near his convoy in the town of Khaldiyah, some 80 km west of Baghdad, the source said, adding that two passersby were also wounded by the blasts. 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. Elsewhere, a police officer and his driver were wounded when a roadside bomb struck their car in the city of Tikrit, a local police source said. Separately, a suicide bomber blew up his explosive-laden car near a police checkpoint near the city of Samarra, wounding two policemen and four civilians, a local police source said. In Iraq's eastern province of Diyala, gunmen wearing military uniforms kidnapped Basim al-Karkhi a Sunni Muslim teacher in al- Sharia (Islamic Law) University after they stormed his house in eastern the provincial capital city of Baquba, some 65 km northeast of Baghdad, a provincial police source told Xinhua. Also in the province, seven soldiers were wounded in a roadside bomb explosion near their vehicle in north of Baquba, while three civilians were wounded by another roadside bomb at a village near the city of Udhiem, some 60 km north of Baquba, the source said.