Amazon steps up spat with Hachette over e-book price
Amazon has said a dispute with publisher Hachette, which has led to price increases and a block on pre-orders, will not be resolved soon.
The two companies are locked in discussions about how to share profits on e-books.
The row will affect US sales and delivery times of books by authors such as JK Rowling.
The retail giant suggested customers used "one of our competitors" to get hold of titles more quickly.
In an uncharacteristically lengthy statement, Amazon said: "We do business with more than 70,000 suppliers, including thousands of publishers.
"One of our important suppliers is Hachette, which is part of a $10bn [£6bn] media conglomerate. Unfortunately, despite much work from both sides, we have been unable to reach mutually acceptable agreement on terms.
"Even more unfortunate, though we remain hopeful and are working hard to come to a resolution as soon as possible, we are not optimistic that this will be resolved soon."
The row concerns the profits made by both publishers and Amazon on books sold digitally.
The two companies are renegotiating the deal, which is likely to lower the price of e-books and hurt the profit margins of publishers.
According to James McQuivey, an analyst for Forrester Research, blocking pre-orders not only hurt early sales, but stopped a vital advertising opportunity - the bestseller list.
"You really have to sell a lot of copies on Amazon, and the pre-sale does that," he told the BBC.
"It looks fabulous - it gets into the New York Times bestseller list, and all that looks wonderful."
'Ability to survive'
Amazon's statement made reference to a deal struck with Macmillan in 2010, which followed a period when Amazon removed the "buy" button from pages offering Macmillan titles.
Authors and other publishers had criticised Amazon for using its power as the biggest player in books in this way.
In a letter to authors, Hachette chief executive Michael Pietsch wrote: "Please know that we are doing everything in our power to find a solution to this difficult situation, one that best serves our authors and their work, and that preserves our ability to survive and thrive as a strong and author-centric publishing company."
The Authors Guild, a US organisation that represents authors, described the tactics as "bullying".
But Amazon has dismissed the comments, and others like it, as "narrow-minded".
It said: "A retailer can feature a supplier's items in its advertising and promotional circulars, 'stack it high' in the front of the store, keep small quantities on hand in the back aisle, or not carry the item at all, and bookstores and other retailers do these every day."