MOSCOW — The snow-covered glass roof of a Moscow water park collapsed Saturday evening onto hundreds of people, killing at least 21 people — including three children — and injuring 106, authorities said.
Initial reports said the roof at Transvaal Park collapsed after an explosion, but Moscow Mayor Yuri Luzhkov and other officials later said there was no evidence of a blast.
Investigators were considering various theories of what caused the collapse, including an accumulation of snow, the difference between the indoor and outdoor temperatures, or the seepage of water into the concrete supports.
Four bodies, including a child, were recovered from the rubble early Sunday, some 12 hours after the collapse, bringing the death toll to 21, the ITAR-Tass news agency reported, citing the Emergency Situations Ministry. Andrei Seltsovsky of the Moscow city health department earlier said three of the dead were children and 19 other children had been hospitalized.
Close to 12 hours after the collapse, rescue workers were still digging through the debris trying to find casualties. Rescuers periodically would order a moment of silence to listen for sounds of life, and rescuers brought in sniffer dogs toward dawn, Ekho Moskvy radio reported.
A child's birthday party was being held in the pool area when the roof collapsed, said Moscow police spokesman Kirill Mazurin.
"There was a loud noise," an unidentified witness told Russia's Channel One television. "Everybody started to run. I started to run. All of the roof over the water zone collapsed."
The roof collapsed about 7:30 p.m. as the water park in Moscow's southwestern suburbs was filled with people basking in its heat while temperatures outside hovered around 5 degrees. About 800 people were in the complex at the time of the collapse, Emergency Situations Ministry spokesman Viktor Beltsov said.
Rescue workers rushed bloodied, moaning people clad in bikinis and swim trunks on stretchers to waiting ambulances, while others clambered out barefoot into the snow.
In footage from inside the park, the NTV television station showed beams apparently made of concrete that had fallen on the park's twisting water slide. A reporter for Ekho Moskvy radio said part of a wall also collapsed.
Roman Yazymin, 29, was tanning in a solarium on the upper floors of the complex when he heard a loud noise and the crash of shattering glass.
"It wasn't an explosion but the noise of metal collapsing," he said.
As he walked through the complex to retrieve his clothing, "everything was in blood," he said.
The accident was caused by "shortcomings in construction or shortcomings in technical maintenance," Moscow prosecutor Anatoly Zuyev said, adding that a criminal investigation would determine whether negligence was involved.
Beltsov appealed to survivors who left the scene to call a telephone hot line so emergency workers could account for all ticket-holders.
Some people initially believed the collapse was caused by an explosion, news reports said. The Russian capital has been on edge since the Feb. 6 bombing in a Moscow subway that killed 41 people and wounded more than 100. President Vladimir Putin blamed Chechen rebels for that attack.
The water park, which opened in 2002, is one of several flashy entertainment venues that have opened over the past couple of years on the city's outskirts. It includes a large pool, an artificial river and a water slide.