Police took eight pro-democracy activists into custody Tuesday for their roles in an assembly July 1 - the first big post-national security-law protest.

Former legislative council members "Long Hair" Leung Kwok-hung, Eddie Chu Hoi-dick and Wu Chi-wai were among the detainees. They alerted supporters via social media before being taken into custody.

The arrest of activist Figo Chan was livestreamed on Facebook. An officer can be heard telling him he was being detained on suspicion of inciting others to take part in an unlawful assembly June 30, as well as participating in a protest the following day.

"This is shameful political suppression," Chan responded.

Three district councilors, Bull Tsang King-shing, Andy Chiu and Lancelot Chan Wing-tai, were arrested with League of Social Democrats member Tang Sai-lai for taking part in an allegedly unsanctioned gathering July 1.

This was the first time police had rejected an application to hold the annual march to commemorate the 1997 handover, citing social distancing rules and the risk of violence.

"You cannot think that as long as a person is regarded as a supporter of democracy, he is free to break the law," Hong Kong chief executive Carrie Lam commented Tuesday about the arrests amid outcry from members of the political opposition.

"In recent days, every time the police arrest people who claim to be pro-democracy activists, they seem to have a protective shield," she added.

This hasn't stopped authorities from charging people under the new national security law and Monday police arrested eight more for participating in a small protest at Chinese University in November which had drawn the ire of mainland officials.

Meanwhile, a church that organized humanitarian aid to protesters during the demonstrations last year announced the bank accounts of its pastor and his wife had been frozen without explanation.

"There is no doubt this is an act of political retaliation," the ministry said in a statement Tuesday.