Germany's IG Metall trade union staged nationwide protests on Thursday against threats to close plants and cut more jobs at Volkswagen, as the VW supervisory board met in the afternoon to discuss new cost-cutting plans for the group.

The meeting was expected to continue into the evening, while protests against the cost-cutting plans took place at more than a dozen sites.

Around 500 people gathered for a rally in Wolfsburg, where the German automotive giant has its global headquarters. They marched with horns and sirens to the management block, where the supervisory board later convened.

Opinions also differ sharply within the supervisory board.

VW chief executive Oliver Blume announced earlier this year that he was working on a new 2030 target for the group and intended to significantly tighten cost-cutting measures.

Up to 100,000 jobs could be cut worldwide, according to Manager Magazin, a German business magazine - twice as many as previously planned.

Four Volkswagen Group plants in Germany are facing closure, according to the magazine: Hanover, Emden, Zwickau and Neckarsulm.

According to Der Spiegel, a news magazine, vehicle production could be wound down at those sites by the end of 2034.

"The precise content of the future plan and the associated required measures are being discussed today between the supervisory board and the management board of Volkswagen AG," a spokesman said ahead of the meeting.

This would involve measures to reduce complexity and focus development and production more regionally. "And yes, we will also have to reduce overcapacity," he said.

IG Metall trade union said it would resist what it called "brutal plans" by the corporate leadership.

"Across the country, colleagues have sent a clear message today: not like this," said union chairwoman Christiane Benner.