(Telecompaper) Apple has unveiled the latest iPhone, with a faster processor, upgraded camera and OS and the 3D touch system for enhanced control of the smartphone's features. The iPhone 6s and the larger iPhone 6s Plus will also go on sale under a new pricing scheme, in monthly payments and with an optional upgrade plan, starting from 25 September in the US and 11 other countries. The new iPhones come with the latest version of Apple's processor, the 64-bit A9 chip, as well as a stronger aluminium and glass casing and display and the new iOS 9 previewed earlier this year. The 3D Touch system senses different levels of pressure, what Apple calls 'Peek and Pop'. Users can press lightly to 'peek' at a photo, email, web page or other content, and press slightly harder to open fully the content. With the Quick Actions feature, 3D Touch allows a simple press on the home screen to go directly to common functions such as sending a message or taking a photo. The 12-megapixel back camera also comes with the new Live Photos feature, to capture the moments immediately before and after the shot was taken in order to provide an enhanced view of the event. Apple has also added optical image stabilisation and support for 4K (3840x2160 resolution) to the video camera on the iPhone 6s Plus. The iPhone 6s and iPhone 6s Plus will be available in gold, silver, space gray and the new rose gold metallic finishes. In the US, they will sell in 24 monthly payments of USD 27 and USD 31 respectively from Apple's retail stores, Apple.com, select carriers and Apple resellers. Apple is also offering an unlocked iPhone 6s or iPhone 6s Plus with the opportunity to get a new iPhone annually and AppleCare+ under the new iPhone Upgrade Program. In addition to the US, both models will launch 25 September in Australia, Canada, China, France, Germany, Hong Kong, Japan, New Zealand, Puerto Rico, Singapore and the UK, with pre-orders beginning 12 September.