Chinese authorities Friday detained Yu Wensheng, a prominent human rights lawyer, just a few days after his law license was revoked after he wrote an open letter criticizing the Chinese president, his family told EFE.

Yu's wife said he was detained around 6.30am, when he left his house in Beijing to take his children to school.

The kids returned home a short while later and told their mother that the police had taken away their father in a big operation, as they saw at least four cars and a score of police personnel.

Yu began to face problems with the authorities after he published an open letter claiming that Xi Jinping was not fit to continue as president for extending totalitarian control over the country.

In the letter, published days before the 19th National Congress of the Communist Party of China held in Oct. 2017, Yu called for reforms in the party to make way for a China that had freedom, democracy, human rights, and the rule of law.

On Monday, the Bureau of Justice sent him a notice saying his license was being revoked on grounds of Yu currently not being employed at any law firm.

The lawyer then claimed in statements to EFE that it was a trick by the government, maintaining that the authorities have been pressuring different law firms against hiring him.

In order not to create "problems" for other colleagues, he recently decided to begin necessary proceedings to create his own law firm, however the authorities have blocked his efforts, Yu added.

He confessed he was expecting it because he had participated in many cases of human rights, confessed the lawyer, who has handled several cases of dissidents and activists.

After Yu's arrest, nonprofit Amnesty International expressed concern that he could be accused of serious crimes such as "inciting subversion against state power," a charge under which activist and blogger Wu Gan was sentenced to eight years in prison in December.

"His detention shows that the Chinese government is less and less tolerant towards criticism of state leaders," Amnesty International researcher Patrick Poon told EFE.

Under the leadership of Xi, who came to power in March 2013, the Chinese authorities have suppressed some of the most prominent human rights lawyers in the country, such as Xu Zhiyong, founder of the New Citizens' Movement, who was sentenced to four years in prison in 2014 amid growing criticism from the international community.

Towards the end of 2017, the nonprofit Human Rights Watch criticized the Chinese authorities for starting a fresh wave of pressures and threats against law firms committed to the defense of human rights.

In 2015, China witnessed a huge wave of repression against human rights lawyers, with hundreds being detained and, according to them, tortured.