A day after a series of blasts killed at least 57 people, the dazed residents of Zaafaraniya are still wondering what hit them. Simultaneous explosions on Sunday (August 13) night included a suicide motorcycle bomber, rockets and a roadside bomb which hit a market in the southern Baghdad district, police said. At least two mortar bombs hit an apartment building in the same area and a car bomb blew up wounding 148 people, they said. But the scale of the destruction spoke of a far bigger attack, perhaps involving large artillery shells or air strikes. U.S. military spokesman Lieutenant Colonel Barry Johnson said there was no American air activity in the area at the time. Three buildings collapsed inwards. A projectile crashed through the roof of one of them and pulverised everything in its path, crashing through three floors of reinforced concrete. "We were sleeping peacefully when we heard a big bang. The house just collapsed. There was not just one blast, four more blasts took place across Zaafaraniya. It is a catastrophe. The blast was very big and we were thinking that the house would fell upon us," Sarmad, a resident described. Iraq's defence ministry said on Monday (August 14) that the destruction was caused by a car bomb and four Katyusha rockets. Iraqis have grown accustomed to the sound of explosions as Sunni Arab insurgents come up with all kinds of bombs in their bid to topple the U.S.-backed, Shi'ite-led government. Explosive devices hidden in everything from soda cans to dog carcasses are part of daily life. But the explosions in Zaafaraniya rattled residents of a city who thought they had seen it all. While large crowds are often bombed, a wave of attacks on buildings is unusual. U.S. military spokesman Major General William Caldwell said on Monday American troops went to the site and determined a gas explosion had triggered other blasts. In Samarra, 50 km (30 miles ) north of Baghdad, a funeral was held in Monday for a prominent Sunni Arab Sheikh killed the day before by gunmen in western Baghdad. Sheikh Baker Mahmoud al-Samaraie was kidnapped by gunmen who were wearing police uniform in the al-Mansour neighbourhood. His body was later found in the street. The funeral took place at a cemetery in Samarra. In the restive city of Ramadi, residents claimed on Monday that U.S. forces burnt down two houses during a raid in the area. They said that the US forces raided al-Iskan neighbourhood in central Ramadi, arresting the men and setting two houses ablaze. "They damaged everything inside the house, they kept us inside a room and seem to want to set fire to our room, they wanted to burn us, the children and women. They damaged our belongings and shouted at us. We have nothing, no bullets, no grenades and no machine guns. They took my three sons, Hussein, Haider and Mohammed. I shall leave them to God," a resident claimed. The US forces did not give an immediate report on the incident. Ramadi, the capital of semi-lawless Anbar province, is a base of the Sunni Arab-led insurgency. U.S. and Iraqi troops have launched a series of offensives in Anbar over the past few months aimed at securing western Iraq against the insurgents. Several incidents were reported across Iraq on Monday. In Mosul, gunmen killed a tribal leader and five civilians in separate incidents. In Falluja, 50 km (35 miles) west of Baghdad, gunmen kidnapped the son of a tribal leader in Falluja and killed a civilian -- again, in separate incidents. In the oil refinery city of Baiji, 180 km (112 miles) north of Baghdad, gunmen killed a tribal leader. Two civilians were killed and three others wounded when a roadside bomb went off near their car in a village near the town of Khalis, 80 km (50 miles) north of Baghdad, police said. And in the central Karrada district of Baghdad, a civilian was killed and three others wounded when a car bomb exploded on Monday. The car bomb was waiting near a gasoline station in the al-Karrada district of central Baghdad when it exploded. Iraqi army sealed off the area immediately after the blast. The United States has boosted its troop levels in Baghdad to try to ease inter-communal bloodshed tearing the capital apart and build confidence in the Shi'ite-led government in power since May. More than 50,000 U.S. and Iraqi troops are taking part in the Operation Together Forward security crackdown in the capital, hoping to prove they can protect Iraqis.