Police in southwest China have detained a Tibetan writer amid scores of detentions in the region hit by anti-Chinese protests, according to a US-based broadcaster Radio Free Asia.

A team of 20 policemen took Gangkye Drubpa Kyab, 33, from his home in Seda county, Sichuan province on Wednesday last week, the broadcaster said, citing acquaintances of the popular author.

Writers, singers, and artists promoting Tibetan national identity and culture have frequently been detained by Chinese authorities, especially following protests against Chinese rule in 2008, it said.

Drubpa Kyab's disappearance comes amid a huge clampdown in Tibetan-inhabited areas following several bouts of deadly unrest, and ahead of the March anniversary of the Tibetan spiritual leader the Dalai Lama's flight into exile.

A government official in Seda told AFP that he was unaware of the arrest of Drubpa Kyab. Police in the county did not answer phones on Sunday.

According to Human Rights Watch, authorities have also detained large numbers of Tibetans for political re-education after they returned from a visit to India to listen to religious teachings.

The New York-based group quoted multiple sources as saying that since February 6, many recently-returned Tibetans had been detained in ad hoc centres in Lhasa, capital of Tibet, and other areas.

The group said the exact number of detainees was not known, but may run into the hundreds.

China has imposed virtual martial law in numerous Tibetan-inhabited regions as tensions have escalated, leading to the deaths last month of at least two people in clashes between police and locals in Sichuan, which borders Tibet.

Over the past year at least 20 Tibetans, many of them Buddhist monks, have set themselves on fire in protest at what they say is religious and cultural repression.

China accuses overseas groups seeking to split Tibet from the rest of China of fomenting the recent unrest, but rights groups say it stems from growing unhappiness among Tibetans over religious and cultural repression.