The coordinated attack in Tayaran Square involved a suicide attacker who drove up to the day laborers pretending to want to hire them, then set off his explosives as they got into his minibus, Lt. Bilal Ali said. At virtually the same time - 7 a.m. - a bomb exploded in a car parked some 30 yards away.
The blasts set fire to at least 10 other cars, Ali said. He said at least 57 Iraqis, including seven policemen, were killed and 151 people were wounded.
Iraqis gather on the square early in the morning, soliciting jobs as construction workers, cleaners and painters. They buy breakfast at stands selling tea and egg sandwiches while they wait for potential employers to drive up.
Khalil Ibrahim, 41, who owns a shop in the area, was treated at a hospital for shrapnel wounds to his head and back.
"In the first explosion, I saw people falling over, some of them blown apart. When the other bomb went off seconds later, it slammed me into a wall of my store and I fainted," he said.
Police at a nearby checkpoint fired random shots in several directions. Residents rushed to the devastated area to see if friends or relatives had been killed or wounded.
Mangled bodies were piled up at the side of the road and partially covered with paper. Two men sat on a nearby sidewalk, crying and covering their faces with their hands.
"The driver of the minibus lured the people to hire them as laborers, and after they gathered he detonated the vehicle," said another witness, Ali Hussein.
Tayaran Square is located near several government ministries and a bridge that crosses the Tigris River to the heavily fortified Green Zone, where Iraq's parliament and the U.S. and British embassies are located.
About a mile away, two roadside bombs targeting Iraqi police patrols exploded at 8:25 a.m. and 8:40 a.m., wounding two policemen and seven Iraqi civilians, said police Capt. Mohammed Abdul-Ghani.
On Monday, at least 66 people were killed or found dead in the Baghdad area and northern Iraq. They included 46 men who were bound, blindfolded and shot to death in the capital - the latest apparent victims of sectarian death squads.
A Marine helicopter also made a hard landing in a remote desert area of Anbar province, injuring 18 people, the third U.S. aircraft to go down in the insurgent stronghold in two weeks.
The U.S. military announced that three American soldiers were killed in a roadside bombing north of the capital on Sunday, putting December on track to be one of the deadliest months of the war. At least 2,934 members of the U.S. military have died since the U.S.-led invasion in March 2003, according to an Associated Press count.
The military relies heavily on air travel to transport troops and ferry officials and journalists to remote locations and to avoid the dangers of roadside bombs planted by insurgents.
The CH-53E Super Stallion, the U.S. military's largest helicopter, was conducting a routine passenger and cargo flight with 21 people on board when it went down about noon Monday, the U.S. command said, adding that hostile fire did not appear to be the cause.
Nine of the 18 injured were treated and returned to duty, it said. The military did not give the exact location where the hard landing occurred, saying recovery efforts were under way.
On Dec. 3, a Sea Knight helicopter carrying 16 U.S. troops went down in a lake, killing four. On Nov. 27, a U.S. Air Force fighter jet crashed in a field, killing the pilot. Both took place in Anbar, a volatile Sunni-dominated province west of Baghdad that is the size of North Carolina.
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