The anniversary strikes an especially sensitive nerve in the city this year after China's move to impose national security legislation on Hong Kong, which critics fear will crush freedoms in the financial hub.

It also comes as Chinese media and some Beijing officials have voiced support for protests against police brutality across the United States.

In past years, Hong Kong's candlelight vigils have drawn tens of thousands of people to the city's Victoria Park.

But police said this week a mass gathering would pose a threat to public health just as the city reported its first locally transmitted coronavirus cases in weeks.

Lee Cheuk-yan, the head of the group that organises the annual vigil, says residents will light candles across the city instead, and hold a minute of silence.

With social distancing measures allowing for religious gatherings under certain conditions, some people plan to commemorate the crackdown in churches and temples.

Hong Kong has banned gatherings of more than eight people, a public health measure authorities have repeatedly said had no political motivation.

Australian Associated Press