Apple Inc. has been reported to be starting production for its biggest iPhones so far in China in July.

People familiar with the company's plans said Apple is working on two new larger phones, according to Bloomberg. Two of the sources said one of the models will have a 4.7-inch display and could be shipped to stores around September, while the other model will have a 5.5-inch display and may be available around the same time.

The new devices from the Cupertino, Calif.-based company might face competition from HTC and Samsung Electronics, which have released smartphones that feature displays as large as 5.7 inches.

According to PC Magazine, people have said the phones will include handsets that will be "rounder and thinner than previous models." They added that the iPhones will have "curved glass and enhanced sensors that can detect different levels of pressure."

Images were posted on BGR Monday showing two different replicas of the iPhone 6. The images indicate that the new models might have slightly rounder edges than the iPhone 5, and that the power button will be moved from the top of the iPhone to side.

The release of the new iPhones would mark the second consecutive year that Apple has released two phones, having released the iPhone 5S and the 5C last year, CNN reported. The company had offered only one phone for the previous six years.

The iPhone is responsible for over half of Apple's annual revenue, with the smartphone taking in $91 billion in revenue alone last year, Bloomberg reported. The revenue brought in by the device is more than the combined total sales of Yahoo!, Oracle, Facebook and Twitter.

The material for the new iPhones, called 2.5-dimension glass, was reported to let manufacturers soften the edges of the screen where the bezel meets the smartphone's frame.

Natalie Kerris, spokeswoman for Apple, declined to comment on the rumored iPhones.