Apple Inc is looking at cars and medical devices to diversify its sources of revenue as growth from iPhones and iPads slow, according to a San Francisco Chronicle report.

Apple's head of mergers and acquisitions, Adrian Perica, met with Tesla Motors Inc founder Elon Musk at the company's headquarters last year around the same time analysts suggested that Apple acquire the Model S electric car maker, the newspaper reported on Sunday, citing a source.

The company is also exploring medical devices and sensors that can help predict heart attacks by studying sound blood makes at it flows through arteries.

The company's senior vice president of operations, Jeff Williams, has met with US Food and Drug Administration chief Dr Margaret Hamburg and Dr Jeffrey Shuren, who oversees the agency's approval for medical devices, to discuss "mobile medical applications," the paper reported, citing FDA records.

Apple could not be reached for comment.

Rival Google Inc recently bought thermostat maker Nest Labs for $3.2 billion, robot maker Boston Dynamic and artificial intelligence startup DeepMind Technologies Ltd. The company has also been working on projects including Google Glass and self-driving cars.

Investors hope that Apple, which last came out with a new device - the iPad - in 2010, has something up its sleeve for 2014. Speculation currently revolves around a smartwatch or even a long-rumored TV product.

Apple is expected to launch the iPhone 6, a mid-range smartphone, and may also launch wearable devices such as iWatch, in the second half of the year.

Others say Apple can use its huge iPhone and iTunes base to get into mobile payments or advertising.

Apple reported lower-than-expected iPhone sales for the holiday shopping quarter and gave a weaker-than-expected revenue forecast. The company has been ceding ground to Samsung Electronics Co and other rivals in China, its No. 2 market.