A person climbs out from under the rubble of a school after it collapsed Friday in Petionville, Haiti. The concrete school building collapsed during classes, killing at least 47 people and injuring many more students.

Petionville, Haiti ? A hillside school where roughly 500 students usually crowded into several floors collapsed during classes on Friday, killing 47 people and injuring many more. Rescuers used bare hands to pull bleeding students from the wreckage.

Neighbors suspected the building was poorly rebuilt after it partially collapsed eight years ago, said Jimmy Germain, a French teacher at the school. He said people who lived just downhill abandoned their land out of fear that the building would tumble onto them, and that the school’s owner tried to buy up their vacated properties.

U.N. military commander Maj. Gen. Carlos Alberto Dos Santos Cruz said the accident is the worst he has seen since coming to Haiti almost two years ago.

At least 39 bodies were brought to the morgue at Port-au-Prince’s General Hospital, Haitian police spokesman Garry Desrosier said.

Another eight people died in a trauma center run by the aid group Medecins Sans Frontieres, or Doctors Without Borders, spokesman Francois Servranckx said. More than 80 others were being treated for injuries by the aid group.

Rescuers worked furiously through the night under floodlights to pull children from the wreckage and give water to those still stuck in the rubble. Thousands looked on from beside the school and across the valley, cheering each time a live student emerged.

But the rescue effort was chaotic and disorganized from the start. The throngs of grieving and screaming onlookers made it impossible for U.N. peacekeepers, Red Cross workers and Haitian authorities to bring trucks and heavy equipment for much of the afternoon.

On Friday night, a truck carrying a backhoe to the scene crashed into several cars. It was not immediately clear whether anyone was injured or whether the truck was privately owned or belonged to the Haitian government.

Police commissioner Francene Moreau says the minister who runs the church-operated school could face criminal charges. Efforts to reach the preacher were not successful.

The concrete building’s third story was still under construction, and Petionville Mayor Claire Lydie Parent told The Associated Press she suspects a structural defect caused the collapse, not the recent rains.

Parent said roughly 500 students from kindergarten through high school attend the school, College La Promesse, in the hills above Port-au-Prince. She did not know how many were inside when it collapsed late Friday morning.

Volunteers arrived with shovels and axes and said they would try to deliver water to those trapped inside.

A swelling crowd erupted with wails and prayers as the injured were carried away and emergency vehicles raced up a winding hill to the school.

“My child, my child!” one mother yelled.

“There are no words for this,” the mayor said as the search for survivors intensified.

Haitian President Rene Preval visited the scene to offer his sympathy, and asked onlookers to come down from surrounding buildings that engineers feared might have been destabilized by the collapse.