Hong Kong’s national security police detained four prominent democracy activists on Wednesday, prompting condemnation from the White House and signaling that the city’s crackdown on political dissidents isn’t yet over.

Among those arrested by the police were 90-year-old Cardinal Joseph Zen, former lawmaker and barrister Margaret Ng, 74, and Canto-pop singer Denise Ho for allegedly "colluding” with foreign forces, according to local media reports. The four were taken to separate police stations before being released later on bail, according to news outlet RTHK.

The arrests are the latest move against democracy activists in the Asian financial hub, which has seen most of its political opposition jailed following unprecedented democracy protests in 2019. The police operation also comes shortly after John Lee, Hong Kong’s former security chief and a vocal supporter of the China-imposed national security law, was selected to be the city’s new leader in a contest where he was the only candidate.