Thousands of German engineering union members have been on strike, in an increasingly bitter pay dispute.
The short walkouts at major companies like Daimler, Siemens and Ford started on Saturday.
The disruption is due to continue until the middle of next week.
The IG Metall union wants an eight percent wage increase for its 3.6 million members.
The engineering sector employers’ group is offering 2.9 percent over 14 months.
The employers have said the pay demands are excessive and the strikes will only hurt the workers’ interests in the long term.
The next round of talks is due on 11 November. If there is no agreement then the union is threatened an indefinite strike.