Helsinki police detained 53 protesters from the climate group Elokapina after a pair of demonstrations in central Helsinki late Friday. After a previously announced 5 pm march on the city's main thoroughfare, Mannerheimintie, protesters moved to the Pitkäsilta bridge, which connects the Kaisaniemi and Hakaniemi neighbourhoods.
The second protest, which began around 6 pm, attracted more activists than at the previous event on Mannerheimintie, which police said involved about 70 people.
Traffic on Pitkäsilta was halted for almost two hours after demonstrators stationed themselves at both ends of the bridge, some attaching themselves with chains and padlocks. Others sat in the middle of the bridge while some played musical instruments.
According to police, some protesters were taken into custody after they ignored orders to leave. Authorities moved demonstrators off the bridge and onto a bus. Traffic on the bridge returned to normal around 8 pm.
After 9 pm police said that the detainees would likely be released later in the evening.
Those who did not obey police orders to leave are suspected of resisting authority, the police department said in a statement.
"In addition to those detained, there were also seven minors present, whom the police suspect of resisting authority," it added.
"The 53 adults and six minor rebels who were detained on Pitkäsilta yesterday have been released during the night," Elokapina said in a tweet on Saturday morning, without elaborating. Elokapina is the Finnish branch of the international Extinction Rebellion movement.
WWF Finland: Biodiversity and climate "two sides of the same coin"
Elokapina had said that the Mannerheimintie march would be the last in a series of "Rebellion for Nature" demonstrations held since 5 October, urging the government to take bolder steps to combat the decline in biodiversity.
A day earlier, the WWF said that the world's wildlife populations have declined by more than two-thirds since 1970 as forests have been cleared and oceans polluted.
"If the progress of climate change does not remain below 1.5 degrees, it will probably become the most central reason for the deterioration of biodiversity," Liisa Rohweder, Secretary General of WWF Finland, said at a press conference.
"Biodiversity and climate change are two sides of the same coin and very important in terms of realising the other goals of sustainable development. If goals related to biodiversity and the climate are not achieved, social and economic goals will also not be achieved," she added.