BlackBerry maker RIM's CEOs resign

Mike Lazaridis and Jim Balsillie, the co-chief executives of Research In Motion, said they have stepped down, handing reins to an insider in the face of heightening criticism of leadership at the struggling Canadian firm that makes BlackBerry smartphones.

Thorsten Heins, a former Siemens AG executive who joined RIM in late 2007 and has risen steadily through its upper management ranks since to become one of the two chief operating officers, took over as CEO on Saturday, the company said.

The appointment ends the two-decade long partnership of Lazaridis and Balsillie, who helped develop the innovative device that was the first to reliably deliver e-mail over airwaves, transforming a tiny Canadian company into a global electronics giant.

Stiff competition from the Apple iPhone and phones using Google´s Android software have severely weakened RIM's grasp on the market and with the company's shares tumbling to eight-year lows speculation was rife that the company is up for sale.

However, investors and critics who have clamoured in recent months for a new, "transformational" leader who would revive RIM's cutting-edge image, could be disappointed as Heins, in an interview on Sunday, pledged to follow the strategy laid out by his predecessors.