FRANKFURT — Deutsche Bank said on Friday that the leader of its investment banking unit would resign, foreshadowing what are likely to be steep cuts in the bank’s operations in the United States and Europe.

Garth Ritchie, the head of Deutsche Bank’s corporate and investment bank, will step down on July 31 “by mutual agreement,” the bank said. Mr. Ritchie’s departure was expected as part of a broader reorganization that is expected to include cutting thousands of jobs and closing unprofitable divisions, particularly in investment banking.

Further announcements are expected as soon as this weekend as Deutsche Bank makes a last-gasp bid to reverse a decade of decline.

Christian Sewing, the Deutsche Bank chief executive, will take direct control of the investment bank, the bank said. The change will give Mr. Sewing a freer hand to push through draconian cuts.