Pat Dollard

BAGHDAD — An explosion near a school in the Sadr City district of Baghdad on Monday wounded scores of children, while attacks on Iraq’s security forces continued.

Government officials gave contradictory accounts of the school casualty figures, with the death toll from the blast varying from one to 15 children and the number of wounded from 41 to 56.

There were competing theories about what caused the blast. In a statement read on state television by Maj. Gen. Qassam Atta, a spokesman for the Baghdad Operation Command, the government said it was the result of an accidental detonation of a cache of explosives hidden near the school. Earlier reports from local security officials, however, suggested that it could have been the result of an errant missile or a planted explosive device.

The disagreement over the basic facts reflected the degree to which Iraqi security forces often lack coordination in responding to attacks.

The force of the blast blew out all the windows in the school, collapsing part of the building and two neighboring houses. In one classroom, a blue backpack stained with blood sat unattended on a desk, books spilling out.

“Where is my daughter?” wailed Hana, 40, a teacher at the school, as she searched through the wreckage. “I can’t find her.”

The explosion took place just as the morning classes for girls were ending and boys were arriving for their lessons. The average age of the students at the primary school was 12.

During the worst years of violence in Iraq, when teachers were frequently assassinated, many schools were closed. Since security has improved and the schools reopened in the past two years, security officials said there have been no reported cases of attacks directed at schoolchildren.

But children have been caught in Iraq’s violence before, most recently when at least 30 were killed in a huge explosion at the Justice Ministry in October. Many attended a day care center in the building.

Over the course of the war, children have been used to get through checkpoints in suicide car bombings. They have been kidnapped, caught in the cross-fire of warring factions, killed in errant missile strikes and in roadside bombings.

The school attacked Monday is tucked away in a narrow alley in an impoverished section of the city. The bomb crater — 15 feet wide and 6 feet deep — was just outside a wall that surrounds the school.

“There was trash being burned outside and a cable from the electricity had just fallen, so my teacher was looking out the window,” said Ritha Kadhim, 12, speaking from his bed in the hospital, one of his eyes closed and swollen, the other filled with blood. Then there was a sudden explosion. “I fell down and everything was dark. One of my friends helped me up. We were all going out when I fell again and the next thing I recall is waking up in the hospital. And now I just want to know if my friends are O.K.”

While it was unclear if the explosion at the school was an accident or not, officials believe militants behind a recent spate of attacks on security forces want to regain a footing in their former strongholds. There have been at least 14 bombings around the country since Friday, with more than a dozen people killed and 80 wounded.