Leading Hong Kong democracy activist Joshua Wong walked free from prison on Monday and vowed to join the anti-government protests which have rocked the Asian finance hub.
Organisers said some two million people marched in tropical heat on Sunday calling for the resignation of Hong Kong chief executive Carrie Lam, protesting a now abandoned bill that would have allowed extraditions to the Chinese mainland.
The city has witnessed an unprecedented expression of public anger against the city's leaders and Beijing, with two record-breaking rallies a week apart punctuated by violent clashes between protesters and police armed with tear gas and rubber bullets.
Wong, one of the leaders of the pro-democracy "Umbrella Movement" protests in 2014, became the latest voice to call for Lam's resignation as he was released from a sentence imposed over his leadership of those demonstrations.
"She is no longer qualified to be Hong Kong's leader," he told reporters. "I will also fight with all Hong Kongers to oppose the evil China extradition law."
Wong was sent to prison in May and was eligible for early release for good behaviour. There is no indication the move was linked to the current protests.