BERLIN (AP) — German police broke up a protest camp housing environmental activists in a forest near the Tesla electric car factory in Grünheide outside Berlin on Tuesday, citing violations of public safety and order.

The protesters had occupied a pine forest near billionaire Elon Musk’s first European Tesla plant since the end of February over concerns about water and deforestation.

Tesla wants to expand its site in Grünheide for a freight station and storage areas and buy a wooded area from the state of Brandenburg, where the plant is based, for that purpose.

Police first were deployed at the protest camp on Monday to temporarily evacuate parts of the camp with tree houses due to a planned search for explosive ordnance from World War II. However, the activists refused to leave and instead climbed high up some of the trees, German news agency dpa reported. Police eventually pulled six people out of tree houses who did not want to leave voluntarily.

Tuesday’s complete breakup of the camp came because the activists repeatedly violated regulations and committed criminal offenses, local police spokesperson Daniel Keip told dpa. He said it was also not possible to establish contact with the leaders of the protests and it could no longer be assumed that the protest would remain peaceful.

The site near the factory has been under investigation for suspected ordnance left from World War II for some time. Unexploded bombs are still found frequently in Germany almost 80 years after the end of the war, and often during work on construction sites. They are usually defused or disposed of in controlled explosions, a process that sometimes entails large-scale evacuations as a precaution.