PORT-AU-PRINCE, Haiti (CNN) -- Rescue workers pulled two uninjured children from the rubble of a school that collapsed the day before, a
spokesman for the International Committee of the Red Cross said Saturday.
The children have been reunited with their families, Rob Drouen said.
The death toll from the collapse climbed to 82 earlier Saturday when rescue workers found 21 bodies in a classroom, Haiti President Rene Preval said, according to the Haitian Press Network.
The bodies included a teacher and 20 students, Preval said, according to Clarens Renois, of the press network.
The president was at the school in Petionville, near the Haitian capital of Port-au-Prince, "Rescue operations are still under way," Renois said.
As many as 700 children were inside when the building collapsed around 10 a.m. ET Friday, officials said. Some were in class and others were in a playground, Haitian media reported.
About 100 to 200 students could be still trapped inside, Renois said. "Maybe they are alive, maybe they are dead."
More than 100 are injured, the Haitian Civil Protection Bureau said.
Preval has said the school was not safe for the number of people inside, Renois said. "This is a very weak construction," he said. "The structure is really weak."
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"We are looking at major casualties here," said Alex Claudon, a Red Cross official on the scene.
Preval and Prime Minister Michele Pierre-Louis toured the disaster area. The Haiti Press Network quoted Preval as saying that he "heard and saw with my own eyes children appealing for help."
At least one member of the Haitian Parliament has raised questions about whether the school was built for the number of students and teachers who were
inside when the College La Promesse Evangelique collapsed, Renois said. The official described the building as "not quite solid" with "weak
construction." 
Watch rescuers pull students from the rubble »
Preval has since called for a review of building-construction guidelines.
The Haitian Civil Protection Bureau said at least 100 people were injured.
Most of the students at the school ranged in age from 10 to 20, officials said, but some are younger. Haitian press reports said kindergarten, primary and secondary students attended the school.
"We are taking all necessary steps. The government has mobilized to save those who can be saved," Pierre-Louis said.
Preval asked residents to stay away to allow police and rescue officials to do their work unimpeded.
Michaele Gedeon, president of Haiti's Red Cross, said that while she was on the phone with rescuers trying to coordinate their efforts, she could hear the voices of distraught children.
"On the phone you can hear so many children, you know, crying, crying, and saying, 'This one is dead, that one is dead,'" she said.
Claudon said hundreds of civilians and rescue workers were digging through the rubble with their hands and rudimentary tools, but "what we need right
now is heavy search-and-rescue equipment." Watch Red Cross official
describe scene »
In a later interview, Claudon said, "Local authorities are doing their best."
About 50 to 60 people, 30 of them severely injured, were taken to Trinite Hospital in Port-au-Prince, said Isabelle Mouniaman Nara, the head of mission in the capital for Doctors Without Borders.
Another 150 patients were treated elsewhere, Nara said Friday night.
The situation at Trinite "is under control right now," she said.
Trinite is the only hospital that is open in Port-au-Prince, Doctors Without Borders said. The other two -- General Hospital and Hospital de la Paix -- have been shut down by labor strikes.
The school is in an extremely poor part of town and the roads are nearly impassable, Renois said. He also said an United Nations helicopter was unable to land.
"The school is poorly built," said Amelia Shaw, a journalist with United Nations TV who visited the scene.
The two-story school had an addition built in the rear over a 200-foot ravine, Shaw told CNN by telephone. The steep hillside, she said, is covered with run-down houses and shacks on both sides.
The disaster happened when the second floor crumbled onto the first, Shaw said.
The U.S. Agency for International Development sent a Disaster Assistance Response Team, which arrived on the scene within hours of the collapse, the agency said in a news release.
U.S. Southern Command said Saturday it will donate $10,000 in medical supplies to Haitian hospitals.
