Fifteen people were killed and 26 others wounded in separate attacks across the country on Monday, police and medical sources said. In Anbar province, artillery and mortar shelling on several neighborhoods in the besieged city of Fallujah, some 50 km west of the Iraqi capital of Baghdad, left eight people killed and 16 others wounded, a medical source from the city hospital told Xinhua. Separately, gunmen shot dead two people and wounded three others in the city of Haditha, some 200 km west of Baghdad, while gunmen shot dead a counter-terrorism officer in the city of Heet, a provincial police source told Xinhua on condition of anonymity. 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, an army officer, a soldier and a shop owner were gunned down when armed men using silenced weapons opened fire on them inside a shop in the northern part of the city of Mosul, a local police source anonymously told Xinhua. In addition, a car bomb went off near an army checkpoint in eastern Mosul, leaving a soldier dead and seven people injured, the source said. Iraq is witnessing its worst violence in recent years. According to the UN Assistance Mission for Iraq, a total of 8,868 Iraqis, including 7,818 civilians and civilian police personnel, were killed in 2013, the highest annual death toll in years.