Officials in the German state of Brandenburg have discovered 187 pounds of World War II-era ammunition at the site of Tesla’s planned factory near Berlin. The Maerkische Oderzeitung German newspaper said as many as 25 unexploded bombs could be located within the area.

Unexploded bombs from World War II still remain a problem for Germany, with the relics sometimes found during construction work in German cities.

On Tuesday, thousands of German workers were forced to evacuate after a bomb weighing over 1,100 pounds was found in the western German city of Cologne. On the same day, authorities defused another bomb in central Berlin.

Tesla announced its “Gigafactory 4” facility in November, with construction beginning in the first half of the year. The factory hopes to better cater to the German and European electric vehicle markets and will likely be completed in 2021. The factory intends to produce 500,000 cars a year.

Protesters have criticized the factory for its water usage and for destroying forests in the area. Brandenburg authorities hope that the factory will create thousands of jobs for the region.