China's President Xi Jinping has arrived in Hong Kong to mark its 20th anniversary of Chinese rule as the city went into lockdown with a massive security blanket ahead of celebrations and protests on Saturday.
Britain returned Hong Kong to Chinese rule in 1997 under a "one country, two systems" formula which guarantees wide-ranging autonomy and judicial independence not seen in mainland China.
Tensions between Hong Kong and China have intensified amid concern and resentment over Beijing's growing interference in the former British colony.
Xi was greeted by supporters waving red Hong Kong and Chinese flags after his Air China plane touched down for the three-day visit.
The trip culminates with Xi overseeing an inauguration ceremony for the Asian financial hub's new leader, Carrie Lam.