Updated

A Tibetan writer says Chinese authorities have detained a highly regarded Tibetan monk and 16 of his supporters, as Beijing tightens its grip over the region.

Tsering Woeser said Friday that rights lawyer Tang Tianhao confirmed the detention of Karma Tsewang, a popular monk in Nangqian county in Qinghai province. The monk is known for his work on disaster relief, environmental protection and teaching youth the Tibetan language.

She said Karma Tsewang was taken away by police Dec. 6 while traveling on business in the city of Chengdu.

Tsering Woeser said at least 16 supporters petitioning for the monk's release have also been detained.

Police said they did not know about the case.

More than 100 people have self-immolated since 2009 to protest China's rule over Tibetan areas.