Instagram, the Facebook-owned popular photo-sharing service, has been blocked in China amid pro-democracy protests in Hong Kong. The move reportedly came after people started posting photos and videos of protests as well as of police firing tear gas at demonstrators on social media websites, including Instagram. Many of the photos circulated by protestors had been tagged with "#OccupyCentral", a hashtag that was blocked on Sunday on Weibo, China's Twitter-like microblogging service.

Although Facebook has been blocked in China for years, Instagram managed to avoid the attention of the country's censors. In fact, the service even managed to grow its user base there. But as photos and videos of protests flooded the service in the past few days, the Chinese government decided to block it.

Website monitoring services like blockedinchina.net and greatfire.org also indicate that Instagram is not accessible from within mainland China. However, the move doesn't affect users in Hong Kong, who continue to post photos and videos onto the service.

The protests, which have left more than 38 people injured, stem from anger over China's new plan for Hong Kong's 2017 election that would effectively bar any democrat from standing, limiting elections to a handful of candidates loyal to Beijing. Hong Kong currently enjoys considerable autonomy under the 'one country, two systems' framework.

China has a long history of censoring the Internet. The country blocked access to Facebook, Twitter, and other popular online services in 2009.