Steel giant thyssenkrupp Chief Executive Heinrich Hiesinger asked the firm's supervisory board to accept his resignation, the Essen-based company announced Thursday. It added that board members were scheduled to meet on Friday to debate Hiesinger's request.

The reasons for Hiesinger's decision were not immediately made public. In the past few months, he had drawn mounting criticism from important shareholders including US hedge fund Elliot and Cevian Capital which had criticized the CEO for dragging his feet on the company's restructuring process.

Last weekend, thyssenkrupp confirmed the planned merger of its steel operations with India's Tata Steel, following more than two years of negotiations. If approved, the tie-up will create Europe's second-largest steel producer with 48,000 employees.

Trade unions breathing down the CEO's neck

Hiesinger had also come under pressure from trade union activists for planned job cuts in the wake of the merger.

The joint venture, in which thyssenkrupp and Tata Steel will have equal shares, is expected to save the two firms up to €500 million ($585 million) annually, in part by cutting around 4,000 jobs.

Trade unions said Thursday they would keep fighting for a lower number of jobs to be slashed.

Hiesinger, aged 58, has been at the helm of thyssenkrupp since 2011. His contract would have expired in 2020.

hg/jd (dpa, AFP, Reuters)