Beijing, Jan 28 (IANS): A Chinese court on Monday sentenced human rights lawyer Wang Quanzhang to four years in prison for subversion of state power.

Wang was arrested in August 2015 during a government crackdown against law firms specialising in human rights cases, which led to the arrests of around 250 lawyers and activists, reports Efe news.

The Tianjin No 2 Intermediate People's Court also deprived Wang of his political rights for a period of five years.

"Today's verdict is a gross injustice. It's outrageous that Wang Quanzhang is being punished for peacefully standing up for human rights in China. He must be immediately and unconditionally released," Amnesty International's China researcher Doriane Lau said in a statement after the sentence.

"The authorities disappeared Wang Quanzhang into a black hole, where he was likely tortured. Wang's family, who continue to be harassed by the authorities, didn't even know if he was alive until recently. His continued imprisonment only prolongs their suffering."

On December 26, undercover police officers blocked Wang's family members - including his wife Li Wenzu - and sympathisers from attending the initial trial hearing in Tianjin.

Foreign journalists and diplomats were also not allowed to attend the trial.

Two days later, Li was again blocked by security forces when she tried to enter the premises of the Supreme People's Court in Beijing in order to file a petition against the Tianjin court for allegedly violating judicial norms in Wang's case.

Wang - who is reportedly in a delicate state of health - has for years defended groups persecuted by Chinese authorities, ranging from members of the spiritual group Falun Gong (banned in China since 1999), to dissidents and activists.

A number of human rights organisations and bar associations have repeatedly urged the Chinese government to release Wang.