Riot police disperse anti-national security law protesters during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

A couple hugs each other as police fire tear gas into the crowds to disperse anti-national security law protesters during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

A person is detained by riot police officers during a march against national security law at the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Riot police use cable tie to detain a man during a march against national security law at the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Anti-national security law protesters march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

An anti-national security law protester holds a Hong Kong independence flag as he marches at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

People detained by riot police during a march against national security law at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

A couple walks past riot police as anti-national security law protesters march during the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2019.

Riot police stop and search people during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

Riot police officers escort a woman to a police bus after detaining her during a march against national security law at the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Riot police use water cannon to disperse anti-national security law protesters during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

Riot police officers walk as anti-national security law protesters march during the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Chinese national flags are seen on the ground during a march against national security law at the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Anti-national security law protesters place bricks on road as a road block during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

People are detained by riot police during a march against national security law at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

Riot police hold pepper-spray projectiles as they disperse anti-national security law protesters during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

(L-R) Pan-democratic legislator Eddie Chu Hoi-dick, Vice convener for Hong Kong's Civil Human Rights Front Figo Chan, and activist Leung Kwok-hung, also known as "Long Hair", march at the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Riot police fire tear gas into the crowds to disperse anti-national security law protesters during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

An anti-national security law protester holds a Hong Kong independence flag as he marches at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

Anti-national security law protesters throw mock paper money during a march against national security law at the anniversary of Hong Kong's handover to China from Britain, in Hong Kong, China July 1, 2020.

Riot police stop and search people during a march against national security law at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

Riot police walk past a fire set by anti-national security law protesters during a march at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.

A man lies on the ground as he is detained by riot police during a march against the national security law at the anniversary of Hong Kong's handover to China from Britain in Hong Kong, China July 1, 2020.