BEIJING (Reuters) - China on Thursday told the embassies of Germany and the United States in Beijing they had no right to criticize an internal affair of China’s justice system, after they called on China to release a prominent human rights activist.

Wu Gan, a blogger better known by his online name “Super Vulgar Butcher”, was sentenced to eight years in jail on Tuesday for subversion. Before his detention in May 2015, he regularly championed sensitive cases involving suspected government abuse of power.

The U.S. and German embassies called on China to release Wu in a joint statement on Wednesday. They also called for rights lawyer Xie Yang, who was also sentence on Tuesday, to be allowed to freely resume his work.

Xie was found guilty of inciting subversion but avoided jail because he admitted to his crimes, the authorities said.

The two embassies had “no right to criticize what was purely an internal affair of China’s and a matter of China’s judicial sovereignty”, foreign ministry spokeswoman Hua Chunying told a regular briefing.

“We hope that the relevant diplomatic missions can take the correct position with regards to their own responsibilities,” she said, adding that China is a country with rule of law and justice officials handled cases in line with the law.

Wu’s sentence was the most severe in what rights groups have called an unprecedented attack on rights activists and lawyers, known as the 709 crackdown, which began in full force on July 9, 2015.

The hardline approach has shown no sign of softening as President Xi Jinping enters his second five-year term in office, and has drawn widespread concern in Western capitals.

Germany has been particularly outspoken, to China’s irritation.