Apple has just responded to the US Department of Justice's litigation over price fixing in the ebook market, telling AllThingsD in a statement that the "accusation of collusion against Apple is simply not true." Two days ago the US filed antitrust charges against Apple and five large book publishers, and while three of those publishers decided to settle with the government on the day the suit was filed, Apple, Macmillan, and Penguin have remain defiant. Here's Apple's full comment from spokesperson Tom Newmayr:

The Department of Justice's accusation of collusion against Apple is simply not true. The launch of the iBookstore in 2010 fostered innovation and competition, breaking Amazon's monopolistic grip on the publishing industry. Since then customers have benefited from ebooks that are more interactive and engaging. Just as we've allowed developers to set prices on the App Store, publishers set prices on the iBookstore.

With the statement, Apple joins Macmillan and Penguin in rejecting the government's charges outright. Yesterday, Macmillan's CEO John Sargent published an open letter in which he said the decision to move forward with Apple's agency publishing model was his alone, and that the DOJ's terms for settling were too extreme. Penguin Group chairman John Makinson released a similar statement, arguing that the DOJ's complaint "contains a number of material misstatements and omissions, which we look forward to having the opportunity to correct in court." While half of the original group under investigation was quick to acquiesce to the government's terms, the remaining players are making it clear that they're ready to put up a fight.