Ilham Tohti was taken to an unknown location by several dozen police yesterday along with his mother, his wife Guzaili Nu'er told AFP, adding that police had confiscated their mobile phones and computers.
Tohti, 45, is an economist at a university in Beijing and has been critical of China's policies towards Uighurs, who are concentrated in the far western region of Xinjiang, which is regularly hit by unrest.
Police did not carry out any legal procedures while forcibly detaining Tohti in front of his two young children, his wife said.
"It had a big impact on my kids, they have been upset and crying since last night, now I don't even have a mobile phone."
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Police combed through the family house, confiscating several computers and other items including phones and academic writings, she said.
It was not clear what triggered the police action, but Tohti has recently expressed fears on his website and in interviews with foreign media about increased pressure on Uighurs following a deadly attack in Beijing's Tiananmen Square in October.
Tohti has been detained on a number of occasions in the past few years, including for more than a week in 2009 after his website ran reports on riots in Xinjiang which killed around 200 people.
His website, Uighurbiz, was offline today after it published a story about the detention.
Tohti, who lectures at at the Central University for Nationalities in Beijing, did not answer his personal phone today and Beijing police were not immediately available for comment.
The vast Xinjiang region, which borders central Asia, has been hit by a series of violent clashes in the past year, which have killed dozens and which China's government has sometimes blamed on "terrorists".