Campaigners have called on China to drop cases against human rights lawyers and to release those being detained in prison including Xia Lin and Zhou Shifeng.

Xia Lin, who has defended activists in court, and Shifeng, director of a prominent Beijing law firm, face prosecution because of their human rights work.

"The Chinese government's hostility toward human rights lawyers has not eased since the mass arrest of legal professionals last July," said Sophie Richardson, China director at Human Rights Watch (HRW). "This heavy-handed campaign against lawyers can only further diminish public and global confidence in China's justice system."

Xia Lin has been charged with extortion after he borrowed money although none of the people he borrowed from complained. HRW believes he is being prosucuted in retaliation for his defense of Guo Yushan, the head of a leading Beijing think tank, in 2014.

Xia Lin has also defended a hotel worker who killed a government official in self-defense against attempted rape.

Zhou Shifeng faces a life sentence after being charged with subversion, arising from last summer when the authorities detained 300 people across the country including many lawyers and and their assistants. Some are still in custody. 

HRW said the Chinese government has "dramatically narrowed space for free expression and civil society" since President Xi Jinping came to power in March 2013.

Liberal scholars and opinion leaders on social media have been targeted, and the government has asserted Communist Party supremacy and demanded increasing loyalty to the party.

In December last year, Beijing lawyer Pu Zhiqiang was convicted for "inciting ethnic hatred" and "disturbing public order" and given a three-year suspended sentence.

In January this year, Guangzhou lawyer Tang Jingling received five years in prison for promoting non-violent civil disobedience.

Beijing lawyer Zhang Kai was detained incommunicado between August 2015 and March 2016 for providing legal advice to Christians who resisted the government's campaign to remove crosses from churches in Zhejiang province.