Apple announced Tuesday it has begun selling its newly revamped iPad mini tablet with an enhanced "retina" display, for which it had not previously announced a firm launch date. Apple unveiled the new gadget on October 22 at the same time as its larger sibling, the iPad Air, but said the mini would be sold at an unspecified date in November. Apple is the largest single vendor of tablets although its market share has now slipped amid competition from rivals. Analysts say the lower-priced iPad mini accounts for more than half of Apple tablet sales, although the company has not released detailed sales figures. Chief Executive Time Cook said recently that he expects demand to exceed supply for the iPad mini during the key holiday sales period. "It's unclear whether we will have enough for the quarter or not," he said during Apple's earnings call in October. "We know how many we will have, but you really don't know the demand until after you start shipping and so we will see how that goes." Apple did not indicate in which countries the iPad mini would be immediately available. In October, the company said the new tablets would be sold in more than 40 markets worldwide. "The response to iPad Air has been incredible, and we're excited for customers to experience the new iPad mini with retina display," said Philip Schiller, Apple's senior vice president of marketing. "We think customers will love both of these thin, light, powerful new iPads, and we're working hard to get as many as we can in the hands of our customers." The iPad mini is being sold in the Apple online store and by retailers and mobile operators starting at $399 for US customers. The old iPad mini is sold at prices starting at $299.