At least three people were killed and eight injured on Friday when scaffolding collapsed off a 19-storey building under construction in the western Swiss city of Lausanne, police said.
The scaffolding collapsed shortly before 9:30 am (0730 GMT), falling "like a house of cards", according to one witness.
The entire scaffolding structure on one side of the 60-metre (200-foot) tower came down, sending construction workers plummeting to the ground.
Regional police said around a dozen people were directly impacted by the accident in Prilly, on the outskirts of Lausanne, including three construction workers who had died.
Four of those who survived were seriously injured. They and two people who were moderately injured had been taken to nearby hospitals, police said.
Police spokesman Jean-Christophe Sauterel stressed that this was a preliminary toll.
"There are still one or two people reported missing," he told AFP.
An AFP journalists saw yellow-clad firefighters clambering on top of a jumble of twisted metal at the foot of the building, while others worked to stabilise the remaining parts of the scaffolding.
Police said that poor weather conditions were complicating the job.
Sauterel said the cause of the accident remained unclear.
"We see that the scaffolding across the entire facade has collapsed, but we do not know the causes," he said, adding that the public prosecutor's office had opened an investigation.
The RTS public broadcaster reported that initial information indicated the freight elevator used to transport construction workers and material to the top of the building had fallen when it was at around the 13th floor, and brought the scaffolding down with it.
Local retiree Fernand Monot witnessed the collapse shortly after seeing a group of construction workers emerge from a nearby shop with pastries and head towards the elevator.
"I saw the freight elevator going up, and then suddenly I heard a loud noise... Everything collapsed," he said.
"It fell down like a house of cards... It didn't stop, just tac, tac, tac all the way down."
"I think they were in the elevator."
Construction workers at the site, which is due to house up to 200 people when completed, told AFP there had not been any particular safety concerns at the site.
The men, who did not want to give their names, suggested that too much weight in the freight elevator might have caused the accident.
One witness to the accident told RTS that the sound of the collapse was "frightening".
"It lasted at least seven long seconds," said the man, whose name was not given.
"I thought it was a bomb."
