A roadside bomb rocked an eastern Baghdad Shi'ite neighborhood early Wednesday, killing at least 11 people and injuring 19 others when it exploded next to buses used by morning commuters, police and hospital officials said. Meanwhile, the US military said four American soldiers were killed and four others were wounded in two attacks in Baghdad. Three of the soldiers were killed on patrol Tuesday in Al Mashtal, a predominantly Shi'ite neighborhood in eastern Baghdad. The military said they died after their Humvee was hit with an explosively formed penetrator, a type of bomb that the US says Iran has been supplying to Shi'ite armed groups - a charge the Iranians deny. Last week, anti-American cleric Muqtada al-Sadr ordered a six-month suspension of operations by his Mahdi Army group. US officials believe mainstream Mahdi forces have generally stuck by the order but breakaway factions of the insurgent group are continuing attacks. Another soldier was killed during combat operations Tuesday in the west of the capital, the US command said. Also Wednesday, embattled Prime Minister Nouri al-Maliki met behind closed-doors with Iraq's top Shi'ite cleric in Najaf to brief him over efforts to fill cabinet jobs vacated when ministers from the largest Sunni Arab bloc and al-Sadr's movement pulled out to protest the prime minister's policies. After the morning bombing, just before 8 a.m. in the neighborhood of Baladiyat, blood stained the ground around a small crater caused by the explosion. APTN video showed the scene strewn with broken glass and littered with people's shoes and other items. Nine people were killed instantly by the blast, according to police, while a medic in nearby Kindi hospital said two others died there shortly afterward from their injuries. It was not immediately clear who was responsible, but the blast came on the fringes of Sadr City, al-Sadr's stronghold. In a pre-dawn raid in Karbala on Wednesday, US forces captured an Iraqi believed to be working as the local contact to the Iranian Revolutionary Guards Corps's elite Quds Force to supply Shi'ite armed groups with Iranian-made weapons, said US Army Maj. Winfield Danielson III. The suspect is also believed to have helped transport Iraqis to Iran for "terrorist training," Danielson said. The military said it is believed that he is "closely linked to individuals at the highest levels" of the Quds Force. US forces were led to the suspect, whose name was not released, by information from prisoners, Danielson said. Following al-Maliki's meeting in Najaf, the premier told reporters he had also discussed the possibility of forming a new government altogether or putting together one made up of nonpartisan technocrats - though emphasized it was currently only an "idea" that was being considered among others. Al-Sistani, who rarely leaves his Najaf home, did not speak to the reporters gathered outside his home on a small alley near the shrine of Imam Ali, Shi'ite's most revered saint and a cousin of Prophet Muhammad. Al-Maliki also said he was considering declaring Iraq's shrine cities "safe havens" where only the army would be allowed to carry arms. He said the proposal was inspired by the fighting last week in the holy city of Karbala where the clashes between the two rival Shi'ite groups left at least 50 people dead. "It's an idea that will spare us potential problems," he said, adding that the proposal would cover cities that house all religious shrines regardless of sect. Elsewhere, officials in Sulaimaniyah announced that they had indefinitely postponed the start of the school year for primary and secondary schools in an effort to prevent the further spread of cholera in the northern province. Since the disease broke out in mid-August nine people have died and some 70 others have been confirmed with cholera. Another 4,000 are suffering from symptoms like severe diarrhea and vomiting. Schools, which were due to open September 15, will be kept closed until the outbreak is under control, said Hussein Sheik Mustafa, the provinces educational director. "This measure is to protect the pupils," he said in a report in the al-Mashriq newspaper.