The door continues to revolve at Motorola, with the former head of the company's struggling mobile phone division stepping down on Friday.

Stu Reed was president of the mobile devices business until Motorola President and CEO Greg Brown took charge of the division himself in early February. Motorola said at the time that Reed would move into another division, but on Friday it announced he has left the company.

Motorola is searching for a new leader for the devices business. At a Morgan Stanley conference this week, Brown said he was spending about 80 percent of his time running the division. "In fairness to Stu, he inherited a very difficult situation. It needed help and more hands-on experience, so I assumed that responsibility," Brown said.

Motorola has said it is exploring options for its mobile division, including spinning it off. The company has failed to maintain momentum in its mobile phone business since the development of its iconic Razr. In the fourth quarter of 2007, the group lost US$388 million, compared with a profit of US$341 million a year earlier.

Reed's departure adds to a host of recent executive changes at the company. The shake-up started late last year when Ed Zander, who had been president and CEO, handed the reins to Brown. Shortly after, Chief Technology Officer Padmasree Warrior left the company.

This week, reports emerged that Chief Marketing Officer Casey Keller, who took that position in 2006, has also left the company. Motorola could not be reached late Friday to confirm the departure, but Keller's biography is no longer accessible on the company's Web site.

Motorola also appointed Paul Liska as chief financial officer in February. He'll replace Tom Meredith, who had been acting CFO and who plans to remain on Motorola's board to help with the transition. Meredith stepped in after the company's previous permanent CFO quit about a year ago.