A new "security concern" has forced the British book publisher Penguin to stop making electronic editions of its new books available to American libraries. Penguin has also banned the libraries from loaning existing Penguin e-books on their shelves to Kindle owners.

Although Penguin isn't stating the specifics, it is believed that "security" means a copyright issue, rather than anything to do with worms or viruses. The move could be a swipe at Amazon, which has been giving out Penguin books for free on Kindle against the wishes of the publisher.

Last month, Amazon offered to lend free books to Kindle owners on their Prime membership scheme: Some publishers declined to allow their titles to be included in the scheme, but it has been revealed that Amazon has been offering them anyway.

The library pull-out will hit the main supplier of e-books to libraries, OverDrive, which has close links to Amazon. OverDrive offers a "read on Kindle" button on its site, a service that has now been pulled.

Penguin had allowed people to "borrow" e-books from libraries by letting punters temporarily download copies to readers, an unusual move for an established book publisher.

El Reg asked Penguin US for greater clarification; we'll let you know when it gets back to us. ®

Update

An earlier version of this article said that Penguin was among the publishers who declined to include their books in Amazon's book-lending scheme. An Amazon spokeswoman contacted The Reg to tell us that "Penguin’s books were never included in Kindle Owners’ Lending Library". A spokesperson added: "Due to new concerns about the security of our digital editions, we find it necessary to delay the availability of our new titles in the digital format while we resolve these concerns with our business partners."