Port-au-Prince  - Between 30 and 50 students died when a school building collapsed Friday in the Petion Ville suburb of Haitian capital Port-au-Prince, while more than 100 were injured.

The Evangelical Promise school in the area of Nerette collapsed at around 10 am (1500 GMT) Friday, with some 700 students inside, Haitian Radio Metropole reported. The three-storey school educated students from kindergarten to high school.

The number of dead could not yet be officially determined, because many of the children and teachers were likely still trapped in the ruins, Mayor Clair Lydie Parent said.

The children were in their classrooms at the time of the collapse, Michaele Gedeon, president of Haiti's Red Cross told CNN. "The whole school collapsed on the kids," she said.

The cause of the collapse was not known.

"We are having difficulty removing students from the rubble because we don't have heavy duty search-and-rescue equipment," said Alex Claudon, also of the Red Cross. He said the number of casualties could be very high.

Gedeon wasn't at the site, but said she could hear rescuers calming down injured students as she coordinated emergency efforts over the phone.

"On the phone you can hear so many children crying ... and saying, 'This one is dead, that one is dead'," Gedeon told CNN. (dpa)