BEIJING (REUTERS) - Authorities in China's restive far western region of Xinjiang have charged a prominent ethnic Uighur professor with separatism, his wife and lawyer said on Tuesday, in a case which has attracted concern in the United States and Europe.

Police in Beijing last month detained Prof Ilham Tohti, a well-known economist who has championed the rights of the Muslim Uighur community, who come from Xinjiang. He was subsequently taken to Xinjiang's regional capital Urumqi.

Prof Tohti's wife, Guzailai Nu'er, said she had received a notice that his arrest had been formally approved and he was being charged with separatism.

"This is ridiculous. He's never done anything like this. He is a teacher," she told Reuters by telephone from her house in Beijing.

Prof 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," Mr Li said from Urumqi where Prof Tohti is being held in a detention centre.

Reuters was unable to reach the Xinjiang government for comment.

The case against Prof Tohti is the latest sign of the government's hardening stance on dissent in Xinjiang, where unrest in the past year has killed more than 100, including several police, according to state media.

Rights activists say Prof Tohti has challenged the government's version of several incidents involving Uighurs, including what China says was its first major suicide attack, in Beijing's Tiananmen Square in October, involving militants from Xinjiang, by pointing out inconsistencies in the official accounts.

The economics professor at Beijing's Minzu University which specialises in ethnic minority studies, told Reuters in November that state security agents had physically threatened him for speaking to foreign reporters.

Many Uighurs chafe at restrictions on their culture and religion, although the Chinese government insists it grants them broad freedoms.

China has blamed some of the violence on Islamist militants and separatists who want to establish an independent state called East Turkestan.

But rights groups and exiles say China exaggerates the threat to justify its firm grip on energy-rich Xinjiang, which borders Central Asia, Afghanistan, Pakistan and India.