The One X, previously referred to as the HTC Edge or Endeavor, has a powerful quad core 1.5 GHz processor and runs Android 4.0 Ice Cream Sandwich with the HTC Sense 4 user interface overlay.
The smartphone comes with a 4.7-inch 720p high definition touchscreen (1280 x 720 resolution) and an 8-megapixel camera with 1080p video recorder. It has 1GB of RAM and 32GB of internal memory.
HTC said that the One X will also be available in select 4G LTE markets with an LTE-enabled Qualcomm Snapdragon S4 processor, including on AT&T in the US.
The One S also runs Ice-Cream Sandwich with HTC Sense 4, but has a dual core 1.5 GHz processor. It comes with an 8-megapixel camera, 1GB of RAM and 16GB of internal memory.
Users of both new devices can benefit from an additional 25GB of storage for two years, available through HTC's partnership with cloud storage provider DropBox. The phones also come with Beats Audio software for an enhanced audio experience.
HTC said that the One V is a lower end smartphone that has a "unibody design", a 3.7-inch screen and a rear camera, but no front-facing snapper.
"The best moments in life are captured with a photo or remembered by a song, so it was key for the HTC One series to improve these emotional experiences with an amazing camera and authentic sound experience," said HTC Corporation chief executive Peter Chou.
"We are very focused on creating a camera and audio experience customers will love and use often and we believe the HTC One series delivers this in a way never seen on a phone before."
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The HTC One series will begin shipping in April across more than 140 mobile operators and distributors globally. Vodafone has announced plans to stock the One X and One S in the UK.