Smoke is seen as a protester shields with an umbrella at Hong Kong Polytechnic University in Hong Kong, November 11, 2019. Hong Kong riot police fired tear gas at a university campus on Tuesday, a day after a protester was shot and a man set on fire in some of the worst violence to rock the Chinese-ruled city. REUTERS/Shannon Stapleton

Smoke is seen as protesters shield with an umbrella at Hong Kong Polytechnic University in Hong Kong, November 11, 2019. Some railway services were suspended and roads closed across the Asian financial hub for a second day, with long traffic jams building in the morning rush hour. REUTERS/Shannon Stapleton

Demonstrators are seen with shields and umbrellas during an anti-government protest at the Chinese University of Hong Kong in Sha Tin, Hong Kong, November 12, 2019. There were chaotic scenes as passengers streamed out of at least one train that was forced to stop when barricades blocked the rail line. REUTERS/Shannon Stapleton

A protester spray paints graffiti at Hong Kong Polytechnic University in Hong Kong, November 11, 2019. REUTERS/Shannon Stapleton

Demonstrators use a band to propel a rock on a footbridge during an anti-government protest near City University in Kowloon Tong, Hong Kong, November 12, 2019. REUTERS/Thomas Peter

Demonstrators stand with shields and umbrellas during an anti-government protest at the Chinese University of Hong Kong in Sha Tin, Hong Kong, November 12, 2019. REUTERS/Shannon Stapleton