San Francisco  - Apple's iconic founder and chief executive Steve Jobs, 53, said Wednesday that he was taking medical leave from the company, leaving chief operating officer Tim Cook in charge.

The news sparked a storm of comment from analysts, bloggers and Apple's legions of fans on the internet. Many wrote that it was unlikely that Jobs would ever return to the company he founded and twice guided to the vanguard of the technology revolution.

"The Steve Jobs era is over," wrote Joe Wilcox, author of Applewatch. "I actually had expected Steve to step down as CEO. Instead, he is taking a leave of absence. But the end is the same, with the leave stalling the inevitable. He can't run the company, and I don't expect him to continue as chief executive."

Jobs, who battled pancreatic cancer in 2004, said that his decision was prompted by the fact that his illness was "more complex" than the hormonal imbalance that he just last week said was the reason for his gaunt appearance in recent months.

Apple's success is closely associated with Jobs' leadership, and his decision is expected to have a detrimental effect on the company's performance. Regular trading in Apple shares was halted immediately after the announcement, but in after-hours trading the stock plunged almost 8 per cent to 78.84 dollars per share.

"During the past week I have learned that my health-related issues are more complex than I originally thought," Jobs said in the email.

"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 said that he would remain involved in "major strategic decisions" during his absence.

Jobs co-founded Apple in 1976, and was instrumental in helping foster the personal computer revolution by popularizing such technology staples as the mouse and the graphical user interface. However, he was forced out of the company after losing a power struggle with the board in 1985, a move that was followed by a rapid decline in Apple's fortunes.

He returned in 1997 and proceeded to revitalize the ailing company with a focus on design and new technology that yielded such market hits as the iPod and music website iTunes, the iPhone and the iMac. He is also the founder of Pixar Animation Studios.

Analysts and bloggers said that they doubted Jobs would return as promised to the helm of Apple.

"He might as well not return after June, for his health and for Apple's," said Owen Thomas, author of the widely read Valleywag blog. "By leaving things so unresolved, he guarantees it will remain as a cloud over Apple."

Others voiced confidence that the company could continue to thrive without its visionary boss.

"Apple has the best team, the best distribution, the best supply chain, the best management in the business," noted influential blogger Robert Scoble. "Apple is more than just Steve Jobs. Now you're about to find out just how much more."

MichaelGartenberg, author of MobileDevicesToday, agreed.

"It's important to remember that no matter how closely we tie Steve Jobs and Apple together, there's still another 24,999 employees who make up Apple." (dpa)