BEIJING• At least 50 Chinese human rights lawyers and activists have been detained or questioned in recent days in an "unprecedented" police swoop, rights groups said yesterday, with around 20 still feared being held.

"More than 50 lawyers and activists were targeted by police in a nationwide crackdown," Amnesty International said in a statement.

"All the individuals missing since the crackdown began on Thursday are well known for their work on human rights cases."

The best known was Li Heping, who was taken away from his home on Friday after what the New York Times described as a police search and the seizure of his computers.

The scale of the clampdown on the legal profession began to emerge when a friend of lawyers and staff at a single Beijing law firm, Beijing Fengrui, known for its human rights casework, said at least five had been detained in the last couple of days.

"(They) were taken away by police for some 'investigation'... and they were not accused yet," fellow lawyer and close associate Zhang Qingfang told AFP.

Beijing Fengrui was most recently in the news for taking on the case of Zhang Miao, a Chinese journalist detained for nine months after helping a German magazine report on democracy protests in Hong Kong.

Lawyers in Beijing, Guangzhou and Shanghai were all targeted, Amnesty said, but it was often difficult to ascertain whether they had been detained, taken in for questioning or had gone into hiding.

A wide-ranging crackdown on dissent has been under way in China since President Xi Jinping took office two years ago, with scores of government critics detained and dozens jailed.

AGENCE FRANCE-PRESSE