Google plans to launch an online store for electronic books in the first half of next year, offering about half a million books initially in partnership with publishers with whom it already cooperates.

The Web search giant said on Thursday it expected to have between 400,000 and 600,000 ebooks at launch, which could be bought either from Google directly or from other online stores such as Amazon.com or Barnesandnoble.com.

Google's offering will provide strong competition to Amazon's Kindle, the world's most popular ereader. The announcement comes a week after Amazon said it would introduce the Kindle into 100 countries outside the United States.

Unlike ebooks purchased for the Kindle, those bought from Google or its publisher partners will be accessible from any device with a Web browser, including PCs, laptops, netbooks, smartphones and some ereaders.

The device need not be connected in order to read the book, after it has been accessed once.

We're not focused on a dedicated ereader or device of any kind, Tom Turvey, Google's director of strategic partnerships, told journalists at the Frankfurt Book Fair.

The service, named Google Editions, will allow Google to make money for the first time out of one of its books ventures -- which also include a controversial project to scan and index tens of millions of books through partnerships with libraries.

Google will share revenue with publishers and also with online retailers, in cases where readers buy Google-hosted books through a retailer's site. It already partners with publishers to make their books searchable and available for sale online.

Readers will also be able to buy books directly from Google using Google's Checkout payment processing service, which stores a users' bank card details in an account accessed through its email service, gmail.

(Reporting by Georgina Prodhan, Editing by Michael Shields)

Kindle Google Amazon Launch