The United States vowed Tuesday to impose visa restrictions on Hong Kong officials responsible for sentencing 45 pro-democracy leaders and advocates to lengthy prison terms.

The activists were arrested over a single day in 2021 and charged with “conspiracy to commit subversion” for taking part in an unofficial primary election.

In Hong Kong’s largest trial under a controversial national security law, 45 pro-democracy leaders were sentenced to prison terms of up to 10 years. Critics claim the law, imposed by Beijing, has been used to crack down on political dissent in the region.