Apple CEO Steve Jobs will take a leave of absence till end-June because of health problems "more complex" than thought, according to an email Jobs sent on Wednesday to Apple employees.

Jobs has already survived a pancreatic cancer, had described his health problem some days ago as a "relatively simple and straightforward". He had promised to remain at the helm throughout his treatment.

But on Wednesday Jobs announced that it would stop working for Apple until June.

"Unfortunately, the curiosity over my personal health continues to be a distraction not only for me and my family, but everyone else at Apple as well," Jobs wrote in an e-mail to employees Wednesday. "In addition, during the past week I have learned that my health-related issues are more complex than I originally thought."

"In order to take myself out of the limelight and focus on my health, and to allow everyone at Apple to focus on delivering extraordinary products, I have decided to take a medical leave of absence until the end of June," Jobs added.

Chief Operating Officer Tim Cook will take over day-to-day operations in what experts say could be a dress rehearsal for a more permanent CEO performance.

"I have asked Tim Cook to be responsible for Apple?s day to day operations, and I know he and the rest of the executive management team will do a great job," jobs said. "As CEO, I plan to remain involved in major strategic decisions while I am out. Our board of directors fully supports this plan."

Wednesday's revelation, which contained scant detail on Jobs health, comes at a difficult time for the company behind iPod media players and iPhones but now grappling with a slowing product line, rapidly worsening consumer spending and an uncertain succession plan.

Speculation about Jobs' health resurfaced in June 2008, when he appeared dramatically thinner at an Apple event.

Jobs started Apple Computer in Silicon Valley more than 30 years ago. Jobs is a also board member and the largest individual shareholder of Walt Disney Co, a position he took when Disney bought his animation company, Pixar Animation Studio, now known as Disney-Pixar, in 2006.