Warning strikes have begun in Germany’s metal and electrical industries as collective bargaining continues amid Volkswagen’s plant closure plans.

Germany’s IG Metall union launched strikes in the metal and electrical industries early Tuesday, with protests kicking off during the night shift.

The strikes come amid collective bargaining over pay and other conditions for some 3.9 million workers in Germany’s automative and other manufacturing sectors.

According to IG Metall, 250 workers went on strike at the Volkswagen(VW) plant in the city of Osnabrück in northwestern Germany. In Hildesheim, about 400 workers at several companies went on strike during the night.