By Alistair Barr

SAN FRANCISCO (Reuters) - Amazon.com Inc said on Thursday owners of its Kindle e-readers and tablets will be able to lend Harry Potter e-books to each other in a move aimed at encouraging more people to use the devices and sign up for its Prime service.

Amazon, the world's largest Internet retailer, bought an exclusive license from author J.K. Rowling's Pottermore e-book business to make all seven Harry Potter e-book available to lend through the Kindleplatform.

Lending begins June 19 and includes Potter e-books in English, French, Italian, German and Spanish.

Amazon did not say how much it paid for the license, but comments from Chief Executive Jeff Bezos suggested the deal was part of its plans to spend heavily to promote Kindle devices and its Prime service. Prime offers free two-day shipping and video streaming for $79 a year in the United States.

"This is the kind of significant investment in the Kindle ecosystem that we'll continue to make on behalf ofKindle owners," Bezos said in a statement.

Purchased e-books can be lent to other Kindle owners as frequently as once a month. Amazon said the library has more than 145,000 e-books to borrow for free.

(Reporting By Alistair Barr; editing by Jeffrey Benkoe)