Apple CEO Tim Cook will step down from his role leading the iPhone maker and hand the reins to the company's head of hardware engineering, the tech giant announced Monday.

Cook will remain involved with the California company as executive chairman. The leadership transition marks the end of Cook's tenure as chief executive, a role he has held since succeeding Apple co-founder Steve Jobs in 2011.

The announcement did not specify a timeline for the transition or identify the hardware engineering leader who will take over as CEO. Apple has not released additional details about the succession plan or what responsibilities Cook will retain in his new role as executive chairman.

The move represents a significant shift for Apple. Under Cook's leadership, the company grew into one of the world's most valuable companies. The hardware engineering division oversees the design and development of Apple's product lineup. That includes the iPhone, iPad, Mac computers, and other devices that generate the bulk of the company's revenue.

Apple has not announced when the leadership change will take effect or whether shareholders will need to approve the transition.