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One of China's most prominent rights lawyers, Wang Yu, and her lawyer husband have been formally arrested and charged with subversion.

Mrs Wang has been charged with "state subversion", which carries a possible life sentence, and Bao Longjun with "incitement to state subversion".

Both have already been in detention for around six months.

China has been conducting a widespread crackdown on lawyers and their assistants, with scores detained.

Earlier this week, at least seven other human rights lawyers and their associates were formally arrested on similar charges.

Like Mrs Wang and Mr Bao they worked at Beijing law firm Fengrui and had been held in secret since last summer.

Media playback is unsupported on your device Media caption Concern for China human rights lawyers

Correspondents say that while many of the lawyers detained in the crackdown have since been released, the authorities appear to be taking a strong line against Fengrui, which was known for taking on high-profile cases.

Last month another prominent rights lawyers, Pu Zhiqiang, received a suspended jail sentence after a brief trial for "inciting ethnic hatred" and "picking quarrels" in social media posts.

Rights group Amnesty International called that sentence "a deliberate attempt by the Chinese authorities to shackle a champion of freedom of expression".