BEIJING — For months, a group of outspoken young communists has put China’s leaders on edge, organizing a fiery campaign for workers’ rights that has evaded the government’s tight political control.

Now the authorities appear to be deploying a new weapon in their efforts to crush the movement: forcing students to watch videotaped confessions in which detained activists say they spread false information and violated the law.

Student activists, who asked not to be identified for fear of being punished, detailed the existence of the videos in interviews and online posts on Monday. They said that more than 20 students at elite Chinese universities had been forced to watch the videos in recent weeks as a way to pressure them to abandon their activism.

On Monday, the activists said they believed the confessions were coerced and vowed to continue their campaign.