A powerful gas blast ripped through a four-storey building in Prague's historic centre yesterday, injuring 35 people including foreigners, and causing panic in the Czech capital.
Rescuers had feared there could be bodies trapped under the rubble of the heavily damaged office block, but the city's mayor said nobody was believed to have been killed.
The force of the explosion damaged parked cars and two adjacent university buildings, blew out windows in nearby streets and shook apartment blocks across the Vltava river.
"It was a gas blast, not a terror attack," Prague mayor Bohuslav Svoboda said.
Rescuers had voiced fears that sniffer dogs would find several people dead in the rubble, but Svoboda said: "They haven't found anyone... and nobody is reported missing."
"It was a terrible blast, everyone was awfully scared," a woman working at the adjacent journalism faculty of Prague's Charles University said.
"Everyone was running, the blast toppled the bookshelves in the library. In one classroom there were lots of injured students, the librarians had blood on their T-shirts," she added.
"At one department the blast wave broke a window on one side and warped the door on the other so people couldn't get out and had to kick the door open."
Thirty-five people were injured, including two Kazakhs, two Portuguese, one German and one Slovak, said Zdenek Schwarz, the head of Prague's emergency services.
Police sealed off the popular tourist area and evacuated 230 people from nearby buildings, fearing further gas leaks, Prague police spokesman Tomas Hulan said, adding that several hundred officers had been called into action after the explosion.
Injured victims were treated on the spot for cuts, some with blood streaming down their faces and bandages on their heads. Many of them were in shock.
Jan Hora, a structural engineer, told Czech TV the damaged building - a former block of flats now used as office space - had to be supported with poles but would probably not collapse.
The force of the blast shifted the wall of the building by about five centimetres and Hora said the blast probably occurred on the ground floor, where the ceiling was destroyed.
The area's architecture mostly dates back to the 19th century, including the ornate National Theatre, whose adjacent modern section was damaged by the blast.
Prime Minister Petr Necas said he was "deeply affected by the tragedy" in the capital, which welcomed more than 5.4 million tourists last year.
An unnamed student told Czech TV that students and teachers from nearby universities had panicked and ran out when the blast shook their buildings. Some were cut by flying glass.