A note from Citigroup analyst Mark Mahaney obtained by technology news site All Things Digital said that based on the supply chain checks in Asia, Amazon is believed to launch a smartphone in the fourth quarter of 2012.

　　According to the note, Amazon is working with manufacturer Foxconn and the device will run Texas Instruments' OMAP 4 processor. The Kindle Fire, the latest tablet introduced by the e- commerce giant, also uses OMAP processor.

　　The analyst said the smartphone will cost Amazon between 150 and 170 U.S. dollars to build and the company could sell the handset at or near its cost rather than a 30 percent gross margin like many other smartphone manufacturers usually do.

　　The move is expected to further intensify Amazon's rivalry with Apple and Google after the e-commerce giant had made moves on some booming businesses like tablet computer and cloud-computing service.