BEIJING — More than 50 human rights lawyers and activists in China have been “detained, disappeared or summoned by police” in a nationwide crackdown over the past two days, Amnesty International said Saturday.

“We are hearing that some lawyers were told they were being arrested on suspicion of picking quarrels and creating disturbances,” Amnesty’s China researcher William Nee said.

At least five employees of the Beijing Fengrui law firm have gone missing, with some “forcibly taken away” by either police or unidentified men, lawyers at the firm said Friday on Twitter.

The firm is known for taking sensitive cases. It represents Zhang Miao, a Chinese news assistant employed by German weekly Die Zeit, who was detained in October after helping to report on pro-democracy protests in Hong Kong. She was released Thursday.

Others detained include Beijing-based rights lawyer Li Heping, who had represented high-profile clients such as blind advocate Chen Guangcheng, the New York Times reported.

Another prominent rights lawyer, Sui Muqing, was detained in the southern city of Guangzhou after police told him to go outside because something had happened to his car, Nee said.

Send questions/comments to the editors.