The Ende Gelände group said on Twitter that it had broken into Economy Minister Robert Habeck’s office in the northern town of Flensburg.
“We stand in solidarity with all the people who are defending Lützerath!” the group said, posting images of an open window with a banner hanging beneath it.
The western town of Lützerath became a flashpoint for climate protests when the government decided in 2022 to press ahead with plans to demolish it to allow the expansion of a nearby coal mine.
The decision came in spite of a pledge to phase out coal by 2030, but the government – a coalition that includes the Greens – blamed the energy squeeze caused by Russia’s invasion of Ukraine.
Police on Wednesday began evicting around 200 anti-coal activists from the town, an operation that is expected to take several weeks.
“Robert Habeck is largely responsible for the violent eviction of Lützerath,” Ende Gelände said, adding that even phasing out coal by 2030 was
“not compatible with the Paris climate agreement”.
“The Greens have thus once again betrayed their own ideals,” the group said.
READ ALSO: Anti-coal activists resist as German police clear protest camp
Police on Thursday continued with efforts to oust the protesters.
Many of the activists have built structures high up in the trees, while others have climbed to the top of abandoned buildings and barns in a bid to complicate the evacuation effort.
Videos shared on social media show the felling of trees.
A police spokesman in nearby Aachen said some protesters had thrown paint pellets and fireworks at officers.
Police also said they were checking reports of an underground tunnel system beneath the site.
Swedish climate activist Greta Thunberg is expected to join a demonstration near the protest camp this weekend.