FRANKFURT/DUESSELDORF (Reuters) - Thyssenkrupp's planned sale of its steel business is at risk over uncertainy following a leadership crisis at the unit, the German conglomerate's works council head said on Friday.

"Uncertainty among the workforce is at a maximum. Fears about the future of employees and that of the company can be felt everywhere," said Tekin Nasikkol, who also sits on Thyssenkrupp's 20-seat supervisory board.

His comments come after Thyssenkrupp Steel Europe (TKSE) late on Thursday said its chairman, chief executive and five other supervisory and management board members would leave, reflecting a deepening dispute over the steel unit's future.

Thyssenkrupp shares were flat at 0834 GMT after earlier falling by 1.8%.

At the core of the clash lies the question over how deep a planned restructuring of TKSE should be and how much money it needs ahead of a partial sale to Czech billionaire Daniel Kretinsky.

Kretinsky recently bought a 20% stake in TKSE and there are concerns over what the current crisis means for ongoing talks for him to buy a further 30% from Thyssenkrupp, according to people familiar with the matter.

Labour represenatives on Thyssenkrupp's supervisory board have requested an extraordinary board meeting to discuss the current crisis, a spokesperson for the IG Metall union said.

EPCG, the vehicle through which Kretinsky made the deal, declined to comment.

The Alfried Krupp von Bohlen und Halbach foundation, Thyssenkrupp's top shareholder with a 21% stake, also declined to comment.