Two leading Hong Kong pro-democracy activists, Joshua Wong and Agnes Chow, were arrested on Friday, just hours after independence activist Andy Chan was arrested at the city's airport, in the run-up to a major demonstration scheduled on Saturday.
Demosisto Party reported on social media that Wong, the organisation's secretary-general, and Chow, a senior member, were arrested separately and taken to the Wan Chai police headquarters.
The South China Morning Post reported that Wong and Chow are being charged for "unlawful assembly".
Al Jazeera's Wayne Hay, reporting from Hong Kong, said that Wong faced three charges. Al Jazeera later learned that the charges include allegedly taking part in an illegal assembly, as well as organising and inciting protest.
Wong was walking to a train station on Friday morning (23:30 GMT on Thursday), when he was "forcefully pushed into a private minivan", Demosisto said. Two hours later, Chow was also arrested in her home.
"They want to arrest them to show that they have the ability to finish this movement," Isaac Cheng, Demosisto spokesman said in a news conference, adding that the Chinese government wanted to instill fear "on Hong Kong demonstrators".
Both Chow and Wong work as assistants to legislator Au Nok-hin of the pan-democratic camp of the Legislative Council.
"Their arrests are unreasonable and arbitrary and smack of political persecution," said Au.
Wong, 22, was one of the leaders of the so-called Umbrella Movement that brought Hong Kong to a standstill for more than two months in late 2014.
Wong had called for the Hong Kong government to scrap the extradition bill legislation, which ignited the ongoing protests in the semi-autonomous Chinese territory. On Friday, Reuters reported that Beijing was directly involved in the decision to reject protester's demand for Hong Kong Chief Executive Carrie Lam to withdraw the extradition bill.
Chow, is also a prominent activist, who had sought to become Hong Kong's youngest council member. She was disqualified after the government said her party's political platform violated the city's electoral laws.
Meanwhile, Chan was reportedly arrested "on suspicion of rioting and assaulting a police officer", according to the Hong Kong Free Press.
Chan, the leader of the banned pro-independence Hong Kong National Party, was arrested as he was about to board a flight to Japan late on Thursday, the publication added.
As this developed, Bloomberg News reported on Friday that CHRF convenor Jimmy Sham was attacked on Thursday in the Jordan area of Kowloon by two unidentified armed and masked me.
The arrests, detention and attack come as a political crisis in the city continues, with another major rally expected on Saturday.
Saturday marks the fifth anniversary of Beijing's rejection of a call for universal suffrage in the city, a decision that sparked the 79-day Umbrella Movement led by mainly young protesters including Wong.
Permission for a mass rally this weekend was denied on security grounds, raising the likelihood of another weekend of clashes between police and protesters, who will likely come out in defiance of the ban.
In a letter to the rally organisers the Civil Human Rights Front (CHRF), police said they feared some participants would commit "violent and destructive acts".
The organisers later announced that they are cancelling the protest, but the Demosisto Party reportedly encouraged Hong Kongers to still go out and protest, according to Al Jazeera's Sarah Clarke, who is also reporting from Hong Kong.
"This is by no means looking to end anytime soon," she said adding that general strikes are also expected on Monday and Tuesday next week.
Also on Friday, AFP news agency reported that Hong Kong's major airline, Cathy Pacific, had warned its staff that they face dismissal if they join any pro-democracy protest.
The ongoing protests against the city's Beijing-backed government have since evolved into a wider call for greater democracy and an investigation into allegations of police brutality.
Protesters say freedoms in the semi-autonomous city, unique within China, are being eroded by Beijing.
More than 850 people have been arrested in connection with the recent protests since June.
Eddie Chu, a Hong Kong legislator, said that the police is now "casting the dragnet ever wider to include those who are well known."
"There's fear they still hold sway and control the crowd. The arrests are utterly pointless and can even backfire," he added.
"It goes to show how the police and the government totally misjudge how the people get mobilised."
With additional reporting by Violet Law in Hong Kong.
