FILE PHOTO: Chinese photographer Lu Guang attends the Pingyao International Photography (PIP) Festival in Pingyao, Shanxi province, China September 20, 2014. REUTERS/Stringer

BEIJING (Reuters) - An award-winning Chinese photographer has been arrested in China’s far-flung western Xinjiang region, his wife said on Thursday, though it is unclear on what charges he is being held.

Lu Guang, a three-time World Press Photo award winner, had been invited to take part in photography events in the regional capital, Urumqi, in late October, his wife, Xu Xiaoli, said last month.

She lost touch with her husband on Nov. 3 while he was traveling alone in the southern city of Kashgar and has not heard from him since, Xu said at the time.

Xu told Reuters by telephone from New York City, where she lives, that police in Xinjiang’s southern city of Kashgar had informed the family of his arrest.

In a post on Twitter she added that the family had hired a lawyer but they have not received any written notice about the case.

Kashgar police did not answer telephone calls seeking comment.

Lu’s prize-winning work has largely focused on sensitive environmental and social issues in China, including industrial pollution, drug addiction and people living with AIDS.

Beijing has faced an outcry from activists, academics, foreign governments and U.N. rights experts over mass detentions and strict surveillance of the ethnic Uighur minority and other Muslim groups in Xinjiang.

Chinese authorities routinely deny any ethnic or religious repression in Xinjiang and say its measures are needed to combat the influence of religious extremism.