Chinese police said Thursday they were offering up to $16,000 as a reward for information on the "black hands" behind a string of self-immolations in a Tibetan-inhabited region.

Notices have been posted in Gannan prefecture in the northwest Gansu province offering the rewards after several Tibetans set themselves on fire in protest at China's rule of the region.

"Anyone who reports and informs the legal authorities on the people who plan, incite to carry out, control and lure people to commit self-immolation will be awarded 50,000 yuan ($8,000)," copies of a notice posted online said.

"Anyone who correctly informs on the black hands behind the four self-immolation incidents that have already happened will be awarded 200,000 yuan."

Police in Gannan confirmed they had posted the notices and were offering rewards when contacted by AFP.

Nearly 60 ethnic Tibetans, many of them monks and nuns, have set themselves on fire in China since February 2009 to protest against Beijing's rule in Tibet, with the most recent incidents occuring near Labrang monastery.

"An intense military buildup" has appeared in Gannan since Saturday, when the first of three recent self-immolations occurred near the famed Labrang Tibetan Buddhist monastery, the US-based International Campaign for Tibet said.

On Wednesday, the government blamed exiled Tibetan Buddhist leader the Dalai Lama for inciting the desperate acts.

The 1989 Nobel Peace Prize winner has not condemned the suicides of the last few years, preferring to remain "neutral" in his words, but he recently paid tribute to the courage of the protesters.

Many Tibetans in China accuse the government of repressing their religious freedom and eroding their culture, as the country's majority Han Chinese ethnic group increasingly moves into historically Tibetan areas.

China insists that Tibetans are enjoying rising living standards and religious freedom in accordance with law.