Samsung is reportedly planning to release the successor to its flagship Galaxy S4 smartphone in early 2014, a South Korean tech website reports. Manufacturing of the Samsung Galaxy S5 -- possible in two versions, metal and plastic -- will begin in Vietnam in January 2014, ET News reported. Such a release would constitute an acceleration of the company's normal release cycle, reinforcing rumors slow sales of the S4 have forced Samsung to move up plans for its new handset, the website said. The Galaxy S5 may be released in two versions -- a premium model with a metal chassis and flexible screen and a lower-priced model with a plastic casing and regular display, ET News said, quoting an unnamed Samsung official. Internally, the specifications of the two versions are said to be identical, it said, with a reported 5-inch display, 3 gigabytes of RAM, a 16-megapixel camera, and Android KitKat 4.4 as its operating system. A manufacturing start in January would suggest a March or April release date, analysts said.