- At least two people are unaccounted for after the Monday morning explosion
- Blast at film school "most likely a gas explosion," police spokesman says
- Blast happened while classes were in session; 35 taken to hospitals, official says
- Workers are trying to stabilize the building to help in the search for the missing
(CNN) -- An explosion ripped through a film and TV school building in the Czech capital of Prague while classes were in session Monday morning, injuring dozens of people and prompting evacuations of nearby buildings, city fire officials said.
At least two people were unaccounted for, and authorities were working on stabilizing the Film and TV School of Academy of Performing Arts building so rescuers could search for them in the rubble, fire department spokeswoman Pavlina Adamcova said.
The blast at the school in the center of the city was "most likely a gas explosion," Prague police spokesman Tomas Hulan said on state-run Czech TV.
Up to 55 people were injured, Adamcova said. Thirty-five were taken to various hospitals, and others with less serious injuries were treated at the site, Prague emergency services representative Jirina Ernestova said.
Much of the building's first floor collapsed, and windows of neighboring buildings were damaged. Nearby buildings including the National Theatre, across the street from the school, were evacuated.
Marianna Zapotilova was in an office in a nearby building when the blast happened. The office's window was open, and the force of the blast "pushed me away from my computer," she said.
"There was a lot of dust" immediately after the explosion, Zapotilova said. "People in the area were injured, mainly by broken glass from the windows, they had their heads bandaged."
CNN's Sarah Balter and Jason Hanna contributed to this report.
