Grieving relatives alleged US troops had used sweets and candy to lure children to the inauguration of a new sewage plant at al-Amil neighbourhood minutes before explosions tore through the crowd on Friday.
"I blame the Americans for this tragedy. They wanted to make human shields out of our children. They should have kept the children away from danger," said Abd al-Hadi al-Badri, a cleric at al-Mubashrun al-Ashra mosque, breaking down in tears.
Al-Badri's son lost his right leg in the explosion after he ignored his father's warnings to stay away from the US troops.
With school holidays coming to an end, children crowded the inauguration in large numbers in response to appeals by US troops through loudspeakers.
"I blame the Americans for this tragedy. They wanted to make human shields out of our children. They should have kept the children away from danger"
Abd al-Hadi al-Badri
"The Americans are the first terrorists and the people who carried out the attack are the second terrorists," al-Badri said.
Al-Badri's is a common lament in the battered Iraqi capital.
Confronted by daily bombings, kidnappings, deadly crossfires and soaring violent crime, many Iraqis blame most of their ills on the US presence. Many say that they and their children would not be dying today had the US not invaded their country 18 months ago.
About 100 yards from the site of two of the three explosions, a large red and yellow tent was filled with mourners for two sisters, Raghad Dharar, 12, and Maysun Dharar, 10, who were killed as they returned from a nearby market.
"The day before yesterday, I bought them new school dresses and I was planning to buy them shoes. I did not know that they were not going ever to attend again," the father said.
Dharar Ahmad, a policeman, said that there was no reason to stage a large celebration for a small sewage plant that was already partially operating.
"The Americans were attracting the children by offering sweets. They should not have done this," he said amid the sounds of wailing women.