Climate activists said Tuesday that they will stage further protests in Berlin in an effort to force the German government into doing more to curb global warming.

The announcement came as courts are taking a tougher stance against members of the group Last Generation who have repeatedly blocked roads across Germany in the past year.

The group said at a news conference in Berlin that it would begin to stage open-ended protests Wednesday in the government district. From Monday onward, members will try to “peacefully bring the city to a standstill,” it said.

Last Generation accuses the German government of breaching the country’s constitution, citing a supreme court verdict two years ago that found too much of the burden for climate change was being placed on younger generations. The government under then Chancellor Angela Merkel subsequently raised its targets for cutting greenhouse gas emissions, but activists say the measures aren’t consistent with the Paris climate accord.

“As long as there’s no plan we can trust to protect our lives and future, and that’s based on the constitution, we are obliged to demand such a plan with all peaceful means,” said Carla Hinrichs, a spokesperson for Last Generation.

The group wants Germany to end the use of all fossil fuels by 2030, a step that would be extremely ambitious to achieve. The country switched off its last three nuclear plants over the weekend, increasing its reliance on coal and gas-fired power plants until sufficient renewable energy capacity is available.

Last Generation’s protests have drawn sharp criticism from across much of the political spectrum, though there has also been support for their underlying aims.

Three activists were sentenced to between three and five months imprisonment by a court in the southwestern city of Heilbronn on Monday. The judge noted that they had joined a blockade in March hours after being sentenced in a previous case.

One of the protesters, Daniel Eckert, defended his actions after the verdict, saying: “As long as the true criminals aren’t brought before a court but instead continue to destroy the basis of our existence and profit from it, I can’t do anything other than stand in the way of this destruction.”