Hong Kong’s most prominent student activist Joshua Wong has called for the resignation of leader Carrie Lam, after walking free from prison.
Wong, 22, became the face of the 2014 pro-democracy protests which called for the city to pick its own leaders.
People in Hong Kong are again out on the streets, this time against a controversial bill which would allow extradition to mainland China.
China has said it will continue to support Ms Lam.
Organisers say more than two million people rallied against the extradition bill on Sunday, despite it being suspended. Police put the figure at 338,000.
Critics have said the legislation would expose people in Hong Kong to China’s deeply flawed justice system and lead to further erosion of the city’s judicial independence.
Much of the public anger has been directed at Ms Lam, who is pro-Beijing, and on Sunday she apologised for the controversy over the bill.
After diminishing in numbers overnight, large groups of protesters gathered near the government headquarters again on Monday.
Demonstrators are pushing for the bill to be scrapped completely, for those jailed during the protests to be freed and for the resignation of Ms Lam.
Wong left prison on Monday after being jailed in May on contempt charges related to his involvement in the pro-democracy protests known as the Umbrella Movement.
Speaking to the BBC he said he was ready to “join the fight” against the extradition bill, and called for Ms Lam to step aside.
“It’s time for her to end her political career,” he said, saying she had “allowed police to hold a gun to the citizens of Hong Kong”.
“It’s hard for us to accept that Carrie Lam, the leader of Hong Kong, copy the model of the Tiananmen Square massacre to such a modern global financial centre,” he added, referring to China’s bloody crackdown on pro-democracy protests in 1989.