Scores of Extinction Rebellion activists blocked access to Norway's oil and energy ministry for more than five hours on Monday, before police cleared the demonstration and made arrests.
Around 17 campaigners, some with "Ban oil" written on their palms, occupied the ministry's reception, while dozens of others demonstrated outside, stopping people getting into the building in central Oslo.
They described the blockade as a part of a 10-day protest against Norway's oil industry. Norway is Western Europe's largest producer of crude and natural gas and pumps some four million barrels of oil equivalent per day.
Police started clearing the building by the afternoon and said they arrested 19 people, most of the people inside the ministry. Another 29 protesters were arrested when they blocked a major road in the city, the force said on Twitter.
Climate change has become a focal point of debate ahead of an election on Sept. 13, in which Norway's center-left opposition is expected to defeat the incumbent Conservative-led coalition.
"For decades we have written letters, we have spoken out, we have demonstrated. You let us speak but you are not listening," 22-year-old activist Hanna Kristina Jakobsen told the crowd during the demonstration.
"This is why we do peaceful civil disobedience now. We are desperate."
Norway's Minister of Petroleum and Energy, Tina Bru, said she shared the worry about climate change but criticized the protesters' tactics.
"We'll never succeed in the fight against climate change if we scrap democracy on the way," Bru said in a statement.
Extinction Rebellion is also planning protests elsewhere in Europe, with two weeks of demonstrations starting on Monday in London.
Earlier this week Extinction Rebellion activists blocked access to an Equinor-run oil export facility on Norway's west coast, temporarily halting the loading of oil.
(Reporting by Gwladys Fouche, Terje Solsvik, Nerijus Adomaitis and Nora Buli; Editing by Raissa Kasolowsky, Mark Porter and Andrew Heavens)