Mortar battles have erupted between Shiite and Sunni neighborhoods in Baghdad, and the once-mixed city is reeling as the two sides adopt the weapons and tactics of urban civil war. Throughout the capital and in towns and villages within an 80-kilometer (50-mile) radius of Baghdad, whole populations have shifted as Shiite and Sunni flee violence from death squads and suicide bombers to the safety of places where their Islamic sect is the majority. The highly portable though inaccurate mortar is increasingly the weapon of choice as Shiite and Sunni populations separate, because it allows sectarian fighters to fire into a district from a distance. Mortars can be quickly pulled from the trunk of a car and fired over several kilometers, causing death and destruction without the dangers of close-quarters combat or the sacrifice of a suicide bomber. For Arkan Maher, a 28-year-old electrician and father, it was just another workday this week when mortar rounds crashed to earth in a market in the Sunni enclave of Azamiyah. He fell wounded in both legs, an eye and one arm. Maher was near the Abu Hanifa mosque, Sunni Islam's holiest shrine in Iraq and a regular target of Shiite mortar teams. "I saw dozens of wounded people on the ground around me," he said, sitting in his house with bandages on his arm and legs. "Azamiyah has been hit with mortars every day for a week now." Across the Tigris River, in the Kazimiyah neighborhood - site of the most important Shiite shrine in Baghdad - retaliatory mortar rounds have rained down daily as well. Other Shiite strongholds in eastern Baghdad, the Shaab neighborhood and Sadr City, are regularly bombarded as is the dangerous Sunni stronghold of Dora, in south Baghdad. The attacks that have driven the two Muslim sects away from each other in the capital skyrocketed after the Feb. 22 bombing of a revered Shiite shrine in Samarra, north of Baghdad. The destruction of the golden-domed mosque enraged Shiites, particularly members of the Mahdi Army militia. The militia, loyalists of anti-American Shiite cleric Muqtada al-Sadr, stormed out of their Sadr City stronghold and have been on a rampage of revenge killing ever since. Sunnis have fought back with equal vengeance. The Mahdi Army and the larger, Iranian-trained Badr Brigade of Iraq's largest Shiite political bloc, the Supreme Council for the Islamic Revolution in Iraq, also have sunk deep roots in the country's police and security forces. The militia members and offshoot death squads have been largely responsible for running Sunnis from neighborhoods where they were a minority. Sunni insurgents, meanwhile, have been attacking Shiites throughout Iraq, including in Sunni-dominated neighborhoods, in what looks increasingly like a successful bid to ignite a civil war. Iraq's Immigration Ministry says about 1.5 million people are internal refugees, while the United Nations says a similar number of Iraqis have fled the country altogether. That would be about 12 percent of Iraq's prewar population of 26 million, and both figures are probably low estimates. Interior Ministry spokesman Brig. Gen. Abdel-Karim Khalaf - a Shiite, as is his boss, Interior Minister Jawad al-Bolani - sought to blame the mortar campaign solely on Sunni insurgents, claiming it was the work of Saddam Hussein loyalists and extremists of al-Qaida in Iraq. "Al-Qaida is facing a major failure, and Baathists are trying to prove something after Saddam was sentenced to death" last week, Khalaf said in a telephone interview. "These are terrorist, cowardly and dirty acts caused by their failure against Iraqi security forces. Now they fire on civilians from a distance, then flee." Sunnis in Azamiyah blame the Shiites. Khaled al-Waleed said mortar attacks on the neighborhood started after Shiite militias were pushed back in recent bids to invade the district. "If they ever decide to enter Azamiyah again, they will be committing suicide," al-Waleed said. He claimed that the mortars falling on the neighborhood are fired from the Shiite neighborhoods of Oteifiyah, Qahira and Ur. The exchange of mortar fire began in earnest this month when four mortar rounds poured down near Azamiyah's Abu Hanifa Mosque, killing at least five people. The next day three more people were killed in rocket and mortar attacks in the same neighborhood. Two other civilians were killed by mortars in Dora. Mortars also fell on both Sunni Azamiyah and Shiite Kazimiyah over the following days. The Sunni-operated Baghdad Television urged the Shiite-dominated government to intervene. On Tuesday, in apparent retaliation for mortar attacks on Sunni areas, a suicide bomber struck a coffee shop in Kazimiyah, killing 21 people and wounding 25. The next day, a pair of mortar rounds slammed into a field in the Shiite district of Sadr City, killing eight soccer players and fans. Shiite Prime Minister Nouri al-Maliki declared Wednesday night that both neighborhoods were being targeted by "Saddamist" and Sunni extremists firing from Taji, 16 kilometers (10 miles) north of the capital. Sadr City resident Wissam Jabr, 28, pleaded with the government to stop these "terrible acts that target innocent civilians." But Sunnis claim the attacks on their neighborhoods are fired from Shiite districts, a sentiment that percolated to the surface during Friday prayers at the Abu Hanifa mosque. "Azamiyah will remain a stick in the eyes of those who hate us, regardless of mortar bombings and the lack of services," Sunni Sheik Sameer al-Obeidi told worshippers. "We will remain steadfast."