Workers' representatives on Volkswagen's supervisory board will push for heads to roll after the carmaker admitted to cheating U.S. vehicles emissions tests, works council chief Bernd Osterloh told employees in a letter obtained by daily Bild on Tuesday.

"I can assure you that we will do everything possible in the supervisory board meetings this week to ensure the matter is cleared up quickly and that personnel consequences are drawn. And that will not just affect the rank and file, I can assure you," Bild quoted Osterloh as saying in the letter.

Volkswagen's management has come under fire after the German carmaker admitted to cheating U.S. vehicles emissions tests and said 11 million of its cars could be affected worldwide.