Volkswagen workers in Kassel held a torchlight parade as three of the German car maker's plants were hit by warning strikes because pay talks seemed to be stalled.
VW is seeking a two-year pay freeze as part of a plan to cut its labour costs by 30% by 2011, while IG Met all, which represents many of the company's 100,000-plus workforce, is seeking higher pay and guarantees of job security.
The talks are due to resume on Monday against a background of fierce competition and job losses in the German automotive industry.
General Motors is seeking to cut its German workforce by about 10,000.
Workers at Volkswagen plants in Brunswick, Hanover and Kassel walked out and further action is likely unless the talks make more progress than was achieved in yesterday's 14-hour session.
IG Metall chief negotiator Hartmut Meine said: "We don't see a solution at the moment." His opposite number at VW, Josef-Fidelis Senn, said: "One has the impression that IG Metall is moving at a speed that, unfortunately, doesn't fit with reality."