Six victims were recovered from the building in the town of Bad Reichenhall, in Germany's southeastern corner, and another four people had been located inside and were believed dead, said Christoph Abriss, a spokesman for the local council. He added that "there are still people missing," but it was unclear how many.
At least four children were among the victims of the collapse, which occurred at 4 p.m. on a school holiday Monday while about 50 people were inside the rink. Recovery efforts were hampered by persistent heavy snow in the area, and help was called in from neighboring Austria.
Police spokesman Fritz Braun said shortly after daybreak that rescuers had heard knocking sounds from the debris, more than 15 hours after the accident.
Workers with dogs were able to comb the building only several hours after the accident, once the remains of the roof were stabilized. Heavy snowfall clogged roads and delayed the arrival of heavy equipment used to move wreckage.
Police said 18 people were injured - three of them seriously - and were taken to nearby hospitals. Another 16 people escaped without injury, they said. Some 360 rescue workers are at the scene.
Fire service officials initially said the flat roof, the wreckage of which pointed up from the center of the 1970s building at an angle, appeared to have collapsed under the weight of snow.
An official with the town's ice hockey club said he had been told by town authorities 30 minutes before the accident that a regular practice session for youth players was canceled because there was a risk of the facility collapsing.
However, "apparently the public skating was still continuing," Thomas Rumpeltes told The AP.
Local officials said there had been a roughly 8-inch layer of snow on the roof.
Mayor Wolfgang Heitmeier said the weight of the snow had been measured at midday and that it was well below the point at which the hall would have had to be closed.
Heitmeier told reporters that, following heavy snowfall in the afternoon, there had been some concern that those levels could be reached Tuesday, and the planned evening training was canceled as a precaution. The snow was to have been shoveled off Tuesday morning.
However, he said officials did not see any danger on Monday "because the levels were significantly below the limit."
The skating rink is 200 by 100 feet. The building, with large glass windows around its sides, is attached to a municipal swimming pool and tennis court.
Police spokesman Franz Sommerauer said rescue crews had gained access to around half the hall by early Tuesday morning. They were trying to remove the largest chunks of debris with the help of six cranes.
Officials clung on to hope of finding survivors after a 6-year-old girl was rescued with no major injuries more than five hours after the collapse.
Rescue officials, however, expressed concern that anyone still trapped between the debris and the ice would risk hypothermia.
Authorities said families with children were in the building at the time of the accident. Among the confirmed fatalities are a 13-year-old boy, and two girls ages 7 and 8, one of whom was killed along with her mother. A 12-year-old boy who was revived at the scene later died at a hospital.
Police and prosecutors are investigating the accident.
Bad Reichenhall, a town of some 15,000 people, is on the border with Austria and about six miles from the city of Salzburg.