Demonstrators carry a goal post during an anti-government protest at the Chinese University of Hong Kong in Sha Tin, Hong Kong, China November 12, 2019.

A protester receives medical attention during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

A student protester builds a roadblock outside the City University in Kowloon Tong, Hong Kong, China November 12, 2019.

Anti-government protesters vandalise the MTR University station during a protest at the Chinese University of Hong Kong, Hong Kong, China November 13, 2019.

Riot police detain a protester as they standoff with unniversity students at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Riot police standoff with university students at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

A demonstrator points to the smashed windscreen of a damaged car during an anti-government protest at the Chinese University of Hong Kong in Sha Tin, Hong Kong, China November 12, 2019. Graffiti on the car reads, "Murdering students".

A demonstrator throws a rock on a footbridge during an anti-government protest near City University in Kowloon Tong, Hong Kong, China November 12, 2019.

A protester sits amid a road block outside City University in Kowloon Tong, Hong Kong, China November 12, 2019.

A university student runs from riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

A protester uses a slingshot during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Protesters sit near a barricade as university students standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Anti-government protesters take cover during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

An anti-government protester throws a Molotov cocktail at the MTR University station during a protest at the Chinese University of Hong Kong, Hong Kong, China November 13, 2019.

Fire burns after anti-government protesters threw Molotov cocktails at the MTR University station during a protest at the Chinese University of Hong Kong, Hong Kong, China November 13, 2019.

Fire burns after anti-government protesters threw Molotov cocktails at the MTR University station during a protest at the Chinese University of Hong Kong, Hong Kong, China November 13, 2019.

Protesters form a barricade during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

A protester sits at a roadblock outside a dormitory in City University in Kowloon Tong, Hong Kong, China November 12, 2019.

Anti-government protesters take cover during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019. Image used for illustrative purpose.

University students standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Anti-government protesters take cover during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Demonstrators are seen with masks and umbrellas during an anti-government protest at the Chinese University of Hong Kong in Sha Tin, Hong Kong, China November 12, 2019.

A protesters throws a molotov cocktail during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Tear gas shells lie in an umbrella as university students standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Protesters take cover as university students standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Protesters look at a road block outside City University in Kowloon Tong, Hong Kong, China November 12, 2019.

Riot police standoff with university students at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

A protester receives medical attention during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Anti-government protesters take cover during a standoff with riot police at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Anti-government protesters make Molotov cocktails during a protest at the Chinese University of Hong Kong, Hong Kong, China November 12, 2019.

Anti-government protesters vandalise the MTR University station during a protest at the Chinese University of Hong Kong, Hong Kong, China November 13, 2019.