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.

Police have stepped up security since the weekend, ahead of final hearing in biggest prosecution under Beijing-decreed national security law.

The U.S. has described the trial and its guilty verdicts as "politically motivated," and has demanded that the defendants be released.

STORY: Dozens of pro-democracy campaigners are to be sentenced Tuesday in Hong Kong, drawing to an end a marathon trial of 47 democrats in a subversion case that has lasted years.Emilia Wong is the girlfriend of one of the defendants,