Dozens of prominent Hong Kong pro-democracy activists are scheduled to be sentenced Tuesday in the biggest case under a national security law that critics say has crushed political activism in the semi-autonomous Chinese city.

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.

Hundreds queued on Tuesday outside a Hong Kong court ahead of the sentencing of 45 pro-democracy activists in a landmark national security trial that has damaged the city's once feisty pro-democracy movement and drawn international criticism.