By Donny Kwok and Pak Yiu
HONG KONG (Reuters) - Hong Kong police arrested publishing tycoon Jimmy Lai, an outspoken critic of Beijing, and two other pro-democracy activists on Friday on charges of illegal assembly, drawing condemnation from international rights groups.
Lai, a self-made millionaire who has made financial contributions to Hong Kong's pro-democracy movement and has been a target of criticism for mainland Chinese media, was picked up by police at his house, Cable TV and TVB News reported.
Apple Daily, one of the publications under media company Next Digital <0282.HK> in which Lai is non-executive chairman, said he was accused of participating in an illegal march on Aug. 31. The newspaper said Lai had followed a crowd along a central route for two hours on that day, singing hymns and praying.
Veteran democracy activists Lee Cheuk-yan and Yeung Sum were also arrested on Friday on the same charges, Cable TV reported.
"Earlier today, we arrested three local men, aged 63 to 72, for suspected participation in a non-approved gathering," Wong Tung Kwong, senior Hong Kong police superintendent of criminal deployment, told a media briefing.
The three have been charged and will appear in court on May 5, he said. Police did not name those arrested, as per its standard practice. It also gave no further details.
Lai was seen by a Reuters reporter leaving the Kowloon City police station in a black Mercedes on Friday. He gave no comment.
"The charges will not hinder our fight for democracy, freedom and our human right to continue to gather, march and protest," Lee told reporters in front of the Cheung Sha Wan police station.
Lai and Yeung could not be reached immediately for comment.
The arrests come after a period of relative calm in the Asian financial hub following months of intense anti-government protests.
Hong Kong saw one of its worst clashes on Aug. 31, with police firing tear gas and water cannons at pro-democracy protesters who threw petrol bombs.
Authorities in Hong Kong have arrested more than 7,000 people for their involvement in the protests, many on charges of rioting that can carry jail terms of up to 10 years. It is unclear how many are still in custody.
Public anger has grown over the months due to perceptions of China tightening its grip over the city. Beijing denies meddling and blames the West for fomenting unrest.
Lai was previously arrested in 2014 for refusing to leave a key pro-democracy protest site in the center of the city. Following his arrest he resigned as editor in chief of Apple Daily. He has also come under scrutiny from Hong Kong's anti-graft agency when they raided his home in 2014.
Taiwan’s Mainland Affairs Council said in a statement it was concerned about the arrests and called on the Hong Kong authorities to ensure freedoms like the right to protest enshrined in the city's basic law are respected.
Amnesty International said the arrests were "a shameless attempt to harass and silence those in Hong Kong’s pro-democracy movement" and called for an independent inquiry into police's handling of the protests - a core demand of protesters.
Police has repeatedly said it has acted with restraint and has used minimum levels of force.
Hong Kong Democracy Council, a Washington based non- government organization, said on Friday that the arrests were "blatant acts of political suppression by the Hong Kong government and the Chinese Communist Party".
The group said in a statement it was demanding the immediate and unconditional release of Lai and the other pro-democracy activists.
The government did not have an immediate comment when contacted by Reuters.
(Reporting by Donny Kwok, Pak Yiu, Twinnie Siu and Jessie Pang; Additional reporting by Ben Blanchard; Writing by Farah Master and Marius Zaharia; Editing by Muralikumar Anantharaman)