Both are powered by the newly launched iOS 7.
Apple has introduced two new iPhone models: the top-end 5S and a low-cost 5C at a launch event in California, US.
Claimed to be the most advanced iPhone yet, the new 5S model is powered by the new iOS 7 and incorporates the new A7 chip and 64-bit technology, which boosts performance during opening apps, editing photos, as well as playing graphic-intensive games.
Features of the iPhone 5S include a new 8mp iSight camera and Touch ID fingerprint sensor that enables secure unlocking of phone with a finger touch, while also offers authentication for purchases from Apple’s website.
Apple Worldwide Marketing senior vice president Philip Schiller said: "iPhone 5S is the most forward-thinking smartphone in the world, delivering desktop class architecture in the palm of your hand."
Apple’s low cost-version iPhone 5C is also powered by iOS 7 and comes with a 4in Retina display, A6 chip, and the 8mp iSight camera, in addition to more LTE bands and new FaceTime HD camera.
"iPhone 5C is everything iPhone 5 was and more, in an all-new design packed with great features," Schiller added.
Scheduled to go on sale from 20 September 2013 in the US, UK, China, Australia and Canada, the new iPhone 5S will be offered in 16GB, 32GB and 64GB storage versions, while iPhone 5C will be available with storage capacities of 16GB and 32GB respectively.
Apple also launched the new OS, iOS 7, boasting an upgraded user interface and several new features, which include Control Center, Notification Center, enhanced Multitasking, AirDrop, improved Siri, among several others.
Designed for both iPhone 5S and iPhone 5C, the new OS also comes with iTunes Radio, which is a free Internet radio service based on the music you listen to on iTunes.
The new OS can be downloaded as a free software update for existing iPhone 4, 4S and 5 models, in addition to iPad, and iPod devices from 18 September 2013.
Apple Software Engineering senior vice president Craig Federighi said: "iOS 7 is completely redesigned with an entirely new user interface and over 200 new features, so it’s like getting a brand new device, but one that will still be instantly familiar to our users."