US troops killed the al-Qaida in Iraq mastermind of the bombing that destroyed the golden dome of a famed sacred Shiite shrine last year and set in motion an unrelenting cycle of sectarian bloodletting, the military said Sunday. Haitham Sabah Shaker Mohammed al-Badri, the group's Salahuddin province emir, was killed in a US operation east of Samarra on Thursday, the military said. He also was responsible for the June 13 bombing that toppled the Askariya shrine's twin minarets, it said. Rear Adm. Mark Fox, a US military spokesman, said al-Badri had been among insurgents spotted by US aircraft moving into "tactical fighting positions." "From the surveillance that was going on, it looked like they were setting up an ambush," he told reporters in the heavily guarded Green Zone. "So they brought in rotary wing and close air support and there was some strafing that occurred from helicopters." "Al-Badri's body was positively identified by close associates and family members," Fox said. Another 80 suspected insurgents were detained in US and Iraqi raids in the Samarra area over the past week, the US military said in a statement. More than 1,000 Iraqi soldiers and police took part in the giant operation, backed by US paratroopers, it said. Four US soldiers were killed in separate attacks in and around Baghdad, the military said Sunday. Two soldiers died of wounds suffered during fighting on Sunday in the capital. A soldier also died and two were wounded Saturday during combat operations in western Baghdad. Another died of wounds suffered when a roadside bomb detonated near a US vehicle the same day, during combat near Baghdad. The names of those killed were withheld pending family notification. At least 3,668 members of the US military have died since the Iraq war started in March 2003, according to an Associated Press count. Meanwhile, 13 people were killed early Sunday and 14 wounded by mortar shells in southeast Baghdad, police said. At least three mortars hit the Mashtal area on the eastern side of the Tigris River, a police officer said on condition of anonymity out of security concerns. It was unclear whether they were aimed at the area, or whether the shells fell short of their intended target. Mashtal is a Shiite-dominated neighborhood in southeast Baghdad. Its main intersection, where the gas station is located, leads to other Shiite slums such as Kamaliyah, Fudailiyah, and Sadr City. Police and witnesses said two of the mortar shells landed near a gas station where people were lining up for fuel at the start of the work week. Many of the victims were burned by fuel that burst into flames from the attack, the officer said. AP Television News footage showed at least two cars with their windshields and windows shattered. The tail fin of a mortar shell was lodged in the ground nearby. Pools of blood soaked into the dusty ground outside crude cement block homes. "Shrapnel hit my front window ... then two explosions took place," said minibus driver Ali Abdul-Karim, 28. "Other drivers and I ran fast toward the sound of the explosions, to help evacuate the victims." Abdul-Karim described a ghastly scene, with rescuers scurrying to discern the wounded from the dead. "I saw two elderly women bleeding and laying on the ground. I don't know whether they were injured or dead," he said. "I also saw three seriously wounded boys laying near their jerry cans. A man was running and screaming, with his hands on his belly, which was cut by shrapnel." The wounded lay bandaged on gurneys at a nearby hospital. Male relatives of the victims, many in clothes stained with their loved ones' blood, milled around outside the neighboring morgue, where at least eleven bodies were visible on metal shelves. The Askariya shrine in Samarra, 95 kilometers north of Baghdad, is one of the holiest places for Shiites. The first attack that destroyed its golden dome unleashed a flood of reprisals - of Shiite death-squad murders of Sunnis, and Sunni bombing attacks on Shiites. At least 34,000 civilians died in last year's violence, the United Nations reported. Despite heightened security put in place after the February 2006 bombing, suspected al-Qaida militants managed to infiltrate the compound and bring down its two minarets in June. For many Shiites, the two minarets were symbols of resilience in the face of a tireless Sunni insurgency - and the attack dealt a bold blow to hopes for reconciliation. Also Sunday, six gunmen were killed and ten others arrested during clashes with Iraqi soldiers in Mosul, 360 kilometers northwest of Baghdad, the Iraqi Army said. Brig. Mutaa al-Khazrachi said the fighting erupted at about 11 a.m., when an Iraqi Army patrol was ambushed in the city's eastern neighborhood of al-Antissar. Fierce fighting was reported in northwest Baghdad around midday Sunday between Iraqi soldiers and members of the Mahdi Army, a militia loyal to anti-American cleric Muqtada al-Sadr. It began when gunmen attacked the convoy of Sheik Hazim al-Araji, one of al-Sadr's aides, after noon prayers in the Kazimiyah neighborhood, police said. Five of al-Araji's bodyguards were injured, but the sheik escaped unharmed, an officer said on condition of anonymity, out of security concerns. The US military said its troops killed four suspects and detained seven others in operations across the country Sunday targeting al-Qaida in Iraq.