Apple Inc. on Monday announced that it sold over 300,000 iPads Saturday, the first day when the tablet computer made a market debut in the United States.

The sales number included deliveries of pre-ordered iPads to customers, deliveries to channel partners and sales at Apple retail stores, the company said.

It added that iPad users downloaded over one million apps from Apple's App Store and over 250,000 ebooks from its iBookstore during the first day.

"It feels great to have the iPad launched into the world -- it' s going to be a game changer," Steve Jobs, Apple's chief executive officer, said in a statement.

Featuring a 9.7-inch touch screen, iPad can let users perform various tasks including browsing the web, watching videos, playing games and reading ebooks.

The iPad was first sold in the U.S. and the models that went on sale on Saturday only have Wi-Fi links to the Internet.

Models that have both Wi-Fi and 3G connectivity are expected to be available in the United States and in Australia, Canada, France, Germany, Italy, Japan, Spain, Switzerland and the UK in late April.

The iPad's first day sales figure was generally in line with analysts' expectations. Still, analysts are cautious about whether Apple's latest gadget can maintain sustained appeal to mass consumers after the initial excitements wane.

Research firm iSuppli predicted ahead of iPad's debut that worldwide sales of the tablet computer could reach 7.1 million units in 2010, double next year and nearly triple to 20.1 million units in 2012.

Sales in 2010 will be driven by early adopters and others attracted to the iPad's unique touch-screen-based user interface, and sales in the next two years will be driven up by factors including a flood of new applications, improved functionality and declining prices, iSuppli said.