Authorities in China's far western region of Xinjiang have charged a prominent ethnic Uighur professor with separatism.
After a month in detention, Ilham Tohti's arrest had been formally approved, and he was being charged with separatism, his wife Guzailai Nuer announced on Tuesday after receiving a notice from the local government.
Last month, police in the capital city of Beijing detained Tohti, a well-known economist who has championed the rights of the Muslim Uighurs, who come from Xinjiang, an autonomous region in the westernmost part of China.
"This is ridiculous. He's never done anything like this. He is a teacher," Nuer told Reuters news agency by telephone from her house in Beijing. Nu'er and Tohti live in Beijing, where he is an economics professor at Beijing's Minzu University.
Tohti's lawyer, Li Fangping, said that he would try and see his client on Wednesday, but he had so far not been given access.
"We'll see how things go in the morning," Li said from Xinjiang's capital Urumqi where Tohti is being held in a detention centre.
Reuters was unable to reach the Xinjiang government for comment.
The case against Tohti is the latest sign of the government's hardening stance on dissent in Xinjiang, often refered to as East Turkestan by ethnic Uighurs, Alim Seytoff, president of the Uyghur American Association, said in an interview with Al Jazeera.
"This indicates a new harder line against all dissent, no matter how it is expressed," Seytoff said.
"Tohti is a man of peace, he is not a violent person and he is a loyal Chinese citizen."
He appealed to the Obama administration to raise the issue with China and to make "a very strong stand" against the arrest.
He said he was doubtful that Tohti could get a fair trial in a Chinese court, and warned that the professor could face years in prison on false charges.
Over the past year, violence in Xinjiang has killed more than 100, including several police, according to state media.
But Tohti challenged the government's version of several incidents involving Uighurs, including what China said was its first major suicide attack, in Beijing's Tiananmen Square in October, involving dissidents from Xinjiang, by highlighting inconsistencies in the official accounts.
Tohti, who specialises in ethnic minority studies, told Reuters last November that state security agents had physically threatened him for speaking to foreign reporters.
By January 15 of this year, he was taken from his Beijing home by several police officers. He was also detained in July 2009, but was released a month after pressure from the Obama administration.
Many Uighurs chafe at restrictions on their culture and religion within Xinjiang, although the Chinese government insists it grants them broad freedoms.
China has blamed some of the violence on armed groups and separatists who want to establish an independent state.