On Monday, amid clashes between protesters and police in Hong Kong, China blocked access to Instagram. William Wan of The Washington Post reported:

Until Monday, Instagram was one of the few foreign social media apps left untouched, even as Facebook, Twitter and other services were blocked.

It has been the vehicle of choice for some dissident artists such as Ai Weiwei. And this weekend, it was a handy way for protesters laying peaceful siege to government headquarters in Hong Kong to send out visual documentation of police charging at protesters with batons and firing tear gas into crowded streets.

According to the Los Angeles Times, “#OccupyCentral” had more than 17,000 mentions on Instagram as of Monday evening. Although Instagram is inaccessible in mainland China, users are still posting from Hong Kong. Here’s a collection of pictures posted from inside the protests: