LUETZERATH, Germany (AP) — Police on Wednesday moved into a condemned village in western Germany, launching an effort to evict activists holed up at the site in an effort to prevent its demolition to make way for the expansion of a coal mine.

Officers in riot gear entered the tiny hamlet of Luetzerath, which has become a flashpoint of debate over the country’s climate efforts. Some stones and fireworks were thrown at advancing police, who could be seen dismantling stalls set up by protesters.

Police announced that the operation had started and that the area would be fenced off. They said on Twitter that people “currently have the possibility to leave the site without further police measures.” They said they had found “further stored projectiles.”

Dozens of activists remain camped out in the village, some in tree houses, as police slowly removed further barricades near the entrance. Some activists read books or played accordion while perched some 10 feet (3 meters) up on tripods.

A few sat on the roofs of Luetzerath’s remaining buildings, one waving a rainbow flag. Conditions were wet and muddy.

Environmentalists say bulldozing the village to expand the nearby Garzweiler coal mine would result in huge amounts of greenhouse gas emissions. The government and utility company RWE say the coal is needed to ensure Germany’s energy security.

On Tuesday, protesters refused to heed a court ruling effectively banning them from the area. Some dug trenches, built barricades and perched atop giant tripods in an effort to stop heavy machines from reaching the village, before police pushed them back by force.

RWE wants to extract the coal beneath Luetzerath, which it says is necessary to ensure energy security in Germany. The company reached a deal with the regional government last year that allows the village to be destroyed in return for ending coal use by 2030, rather than 2038.

But climate campaigners say the agreement to expand the massive open-cast mine goes against Germany’s international commitments to reduce emissions of planet-warming greenhouse gases. They also cite studies suggesting the coal beneath Luetzerath may never be needed.

Luetzerath “is now the European place of crystallization for the climate movement,” said Lakshmi Thevasagayam, a spokeswoman for the Luetzerath Lives activist group. “We are standing against RWE making a meter of progress with its diggers, because we know that the coal under Luetzerath isn’t needed for energy security — it must remain in the ground so that we can achieve climate justice.”

“Now we can do something against the climate catastrophe, but at some point we won’t be able to any more,” Thevasagayam said. She asserted that there had been “a complete escalation” on the part of police.

The head of the Deutsche Polizeigewerkschaft police union’s regional branch, Erich Rettinghaus, said that police were proceeding “very prudently” and were giving demonstrators every possibility to demonstrate peacefully. But he said that there was concern about trouble because potentially violent demonstrators from across Europe had gathered at the site in recent days.

“The protest is a symbolic protest,” he said. “The concerns are understandable; climate protection is important, but energy must continue to be affordable for all,” he added, pointing to the compromise that provides for an earlier end to coal use.

The utility company said in a statement that a 1.5-kilometer (nearly one-mile) fence will be built around the site as one of the first measures.

It said it is “appealing to the squatters to observe the rule of law and to end the illegal occupation of buildings, plants and sites belonging to RWE peacefully.”