Officials from the Espoo rescue service on Thursday said about 27 people, mostly minors, had been hurt when a makeshift pedestrian bridge collapsed.
Finnish daily Helsingin Sanomat said the group was part of an eighth-grade class returning from a field trip.
What we know so far
The accident, at about 9:20 a.m. (0620 GMT/UTC) is believed to have happened when wooden planks beneath the structure gave way.
Police in Espoo, the city immediately to the west of the Finnish capital, Helsinki, said the bridge was made from plywood and was in place because of construction work in the area.
"Several people fell a few meters when the bridge collapsed. The situation is being investigated," police said in a statement.
Officials said a technical investigation would examine the possible causes of the accident in Espoo's Tapiola district.
"Shocking news about an accident in Tapiola," Finnish President Sauli Niinisto tweeted. "Providing support and help now important."
Helsinki hospital service HUS said most of the injuries were limb fractures. Twenty-four of the injured were reported to have been transported to various hospitals in the region.
While the hospital authority said none of the injuries was life-threatening, it added that 10 of the victims had been seriously injured.
