SAN FRANCISCO, Oct 22 (Reuters) - Apple Inc Chief Executive Officer Tim Cook kicked off a product event on Tuesday at which the company is expected to introduce slimmer, faster iPads in time for the holidays.

The new tablets would face stiff competition, with Microsoft Corp, Nokia and Amazon.com Inc all plugging rival devices in coming months.

Apple, which jumpstarted the tablet computing market in 2010 with the first iPad, has already come under increasing pressure from cheaper devices from Amazon's Kindle Fire to Samsung Electronics Co Ltd's Note.