Huburtus von Gruenberg, head of the supervisory board at Continental, has resigned over differences with the group’s new main shareholder, Schaeffler.

The decision would take effect immediately, and von Gruenberg would be replaced temporarily by the current vice president, union leader Werner Bischoff, pending the election of a new president, a statement said.

Dow Jones Newswires quoted von Gruenberg as telling reporters that ‘Schaeffler has breached the spirit …and content of our investor agreement’.

Von Gruenberg said there was a risk that Continental would “be roped in in the downward” spiral embroiling the family-owned Schaeffler.

Schaeffler is in talks with banks and has asked for state aid. The firm borrowed heavily to fund its acquisition of Schaeffler shares.