The U.S. Justice Department has warned Apple and five major U.S. publishers that it plans to sue them, accusing them of driving up prices in the e-book industry, blocking rivals, such as Amazon, from offering cheaper e-books, reports Reuters. The five publishers facing possible Justice Department action are Simon & Schuster Inc, a unit of CBS Corp; Lagardere SCA's Hachette Book Group; Penguin Group (USA); Macmillan, and HarperCollins, a unit of News Corp.