The demonstration was originally organised by the Civil Human Rights Front, who cancelled it when police objected, but protesters still gathered in Central
Apple Daily founder Jimmy Lai Chee-ying was arrested on Friday morning for illegal assembly and intimidating a journalist at anti-government protests in Hong Kong last summer.
A police source said he was held as part of an operation targeting those involved in a march on August 31 during the unrest sparked in June by the now-withdrawn extradition bill.
Several police officers from the crime unit came to Lai’s residence at Kadoorie Avenue, Ho Man Tin, at about 7.30am on Friday and took him to Kowloon City Police Station.
Hong Kong protests: 10 things we didn't know last year that we know now
Two pro-democracy politicians were also reportedly arrested on Friday morning on suspicion of illegal assembly on August 31.
Two sources confirmed that ex-lawmakers Lee Cheuk-yan and Yeung Sum were at their homes when police came.
The Labour Party has confirmed that Lee, a party veteran and general secretary of Hong Kong Confederation of Trade Unions, was arrested at around 8am on Friday.
Pro-democracy protesters take to the streets for New Year's Day march
The party condemned police, accusing them of abusing the power to arrest.
Lee Wing-tat said his Democratic Party colleague Albert Ho Chun-yan had not been arrested, but believed he might be when he arrived at the office later. It is not clear if Ho was at the August 31 rally.
The assembly on August 31 was originally organised by the Civil Human Rights Front, which was behind the city’s biggest anti-government events. But they cancelled it after losing their appeal against a police objection to the march.
Protesters gathered at Chater Garden in Central regardless, before clashes broke out on Hong Kong Island and Kowloon.
Police made arrests at Prince Edward railway station, where they were accused of using excessive force when they stormed a stationary train.
Those behind the rally said it was a religious gathering among Christians to pray for Chief Executive Carrie Lam Cheng Yuet-ngor, who they called a "sinner".
They highlighted a provision of the Public Order Ordinance, which says assemblies exclusively held for religious purposes do not require police approval.