At least four officers and two soldiers have been killed as mortar rounds hit an Iraqi army base west of the capital Baghdad.According to Iraqi security officials, the attack was carried out in the Abu Ghraib area on Monday. The deaths came two days after at least 18 Iraqi military officers were killed in an ambush in the western province of Anbar. The commander of the army’s Seventh Division and the commander of its 28th Brigade as well as several other high-ranking officers were among those killed in the attack. On Sunday, Iraqi Prime Minister Nouri al-Maliki said that an anti-government sit-in site in a city in the Sunni Muslim-dominated province has become a “headquarters for the leadership of al-Qaeda,” urging anti-government protesters camping out for a year to leave the area before security forces move in. The Iraqi prime minister called on the Iraqi forces to take a firm stance to end the sit-in in Ramadi, which is the largest city in the province. According to the United Nations, at least 8,000 people have lost their lives in Iraq so far this year.