HONG KONG: Tens of thousands of people across Hong Kong lit candles and chanted democracy slogans on Thursday to commemorate China's deadly Tiananmen crackdown, defying a ban against gathering as tensions seethed over a planned new security law.

The biggest crowds descended on Victoria Park that has hosted huge Tiananmen anniversary vigils for the past three decades, with smaller rallies erupting in multiple shopping districts and local neighbourhoods. Police arrested some demonstrators in one shopping area, in scenes reminiscent of seven months of violent protests last year, although they allowed the main rally to proceed.

The displays of resistance came hours after Hong Kong's legislature passed a bill criminalising insults to China's national anthem, which the pro-democracy movement sees as yet another example of eroding freedoms.

China also last month moved to impose the security law on Hong Kong which would outlaw subversion and has cemented fears that the semi-autonomous city is losing its treasured liberties. "I've come here for the vigil for 30 years in memory of the victims of the June 4 crackdown, but this year it is more significant to me," a 74-year-old man who gave his surname as Yip told AFP as he joined the crowds inside Victoria Park.

"Because Hong Kong is experiencing the same kind of repression from the same regime, just like what happened in Beijing."