Apple on Monday announced that chief executive Steve Jobs will take a medical of absence.

The company did not say how long the absence will last, but in an e-mail to employees, Jobs said he will continue as CEO and be involved in all the major strategic decisions at Apple.

"At my request, the board of directors has granted me a medical leave of absence so I can focus on my health," Jobs wrote. "I have asked Tim Cook to be responsible for all of Apple's day to day operations."

"I have great confidence that Tim and the rest of the executive management team will do a terrific job executing the exciting plans we have in place for 2011," Jobs continued. "I love Apple so much and hope to be back as soon as I can. In the meantime, my family and I would deeply appreciate respect for our privacy."

Jobs took a medical leave of absence in January 2009 due to hormonal problem that made it difficult for his body to process proteins. It was later confirmed that Jobs underwent a liver transplant. He returned to work in June 2009.

Jobs was also diagnosed with and treated for a rare type of pancreatic cancer in 2004, but he said the 2009 absence was not a resurgence of that cancer.

Cook took over day-to-day activities in 2004 and 2009.

The news comes several weeks before Apple's shareholders are expected to meet and vote on a plan that would require Apple "to adopt and disclose a written CEO succession planning policy," according to a January 7 filing with the Securities and Exchange Commission. Apple is advising shareholders to vote against the proposal.

Apple is also scheduled to discuss its first quarter earnings during a Tuesday afternoon conference call.

Cook appeared last week to introduce the Verizon version of the Apple iPhone. Though no announcements have been made, Apple is expected to release a number of high profile products this year, including the next version of the iPad and the iPhone.