Thousands of US libraries on Wednesday began lending digital books over the Internet for reading on Amazon's popular Kindle devices.

Amazon said more than 11,000 libraries throughout the United States have added Kindle books to virtual shelves at their respective websites.

"Starting today, millions of Kindle customers can borrow Kindle books from their local libraries," said Amazon Kindle director Jay Marine.

Marine added that Amazon was "doing something a little extra" by adding technology that stores highlights, notes or bookmarks made in digital works by borrowers for reference when next they check out the titles.

"Normally, making margin notes in library books is a big no-no, but we're fixing this," he said,

What electronic books are available and durations of loans will be determined by individual libraries. Borrowed books can be sent wirelessly to Kindle e-readers or transferred using USB memory sticks.

Digital books can be read on an array of devices from Apple iPads and iPhones to Android-powered gadgets or desktop computers using free Kindle software applications.

"This is a welcome day for Kindle users in libraries everywhere and especially our Kindle users," said Marcellus Turner, city librarian for the Seattle Public Library.

More information about borrowing Kindle books from libraries is available online at amazon.com/kindle/publiclibraries.