Thousands line up in China ahead of Friday launch of Apple's iPhone 4S

Hours before the iPhone 4S is set to go on sale in China, massive lines with thousands of people have formed outside of Apple's heavily trafficked retail stores.

Throngs of people gathered outside of Apple's stores in China were captured in pictures shared by Penn Olson on Thursday. China Unicom also began reminding its customers that the iPhone 4S will go on sale Friday at 12:01 a.m. local time with text messages.

The pictures show Apple's two stores in Beijing and three in Shanghai with hundreds of people lined up at each. Most of the stores have a ticketing system to help protect everyone's place.

Apple announced earlier this month that it would launch the iPhone 4S in China on Friday, Jan. 13, along with 21 other countries. The device will be sold through China Unicom, which remains Apple's only carrier partner in the nation of over one billion people.

As an added incentive for mobile customers, China Unicom is offering a heavy subsidy on the iPhone 4S at launch. Subscribers will be able to get Apple's newest smartphone model for free with a new multi-year service contract, and as little as $285 yuan ($45 U.S.) per month.

China has become a very important part of Apple's business with tremendous growth in a relatively short period of time. A year ago, Apple executives revealed that the company's retail stores in China were its most visited in the world, only three years after the company opened its first retail store in Beijing in 2008.