BEIJING Tibetan high school students protested in the streets of at least two towns in western China this week to mark the anniversary of an uprising against Chinese rule, and some have been detained, residents said on Thursday.
The demonstrations appear to be the first unrest in tightly controlled Tibetan areas at a highly sensitive time. March is the anniversary of both spiritual leader the Dalai Lama's flight into exile decades ago, and a uprising across the areas in 2008.
Beijing has stepped up its security presence and promised to pour extra cash into development to calm the restive and strategically vital border region.
But critics say if China does not address Tibetan concerns about the loss of their culture and heritage, stability will remain elusive.
At least 20 teenagers were taken into custody by police in the remote western town of Hezuo on Wednesday, shortly after a larger group began a protest, a hotel clerk there said.
Hezuo is in a Tibetan corner of Gansu province.
She declined to give her name, or comment on the motive for the protest, saying "only themselves know".
On March 14, dozens of teenagers also took to the streets of Machu, also in Gansu, chanting pro-Tibetan slogans, said a supermarket manager who himself is Han Chinese. He was not clear if anyone was arrested.
The town is now crawling with military police and feels safe and calm, said the manager, who declined to give his name because ethnic tensions in Tibetan areas are politically sensitive, and discussing them with foreign journalists risks punishment.
A string of checkpoints have also been set up along the road to Langmu temple, around 70 km (43 miles) away, since Sunday, a hotel employee near the monastery said, but added that he did not know the details of what happened in Machu.
The Gansu foreign affairs office and the Gansu provincial information office said they had not heard of any protests. Police in Machu and Hezuo did not answer calls.
Historically Tibetan Machu, surrounded by vast grasslands, is in one of the areas that was worst hit by famines and purges during the rule of Mao Zedong and foreigners have only been allowed to visit since 1999.
Rioting flared in the town on March 16, 2008, the weekend after violence in Tibet's capital Lhasa.
Protests there against Chinese rule, led by Buddhist monks, gave way to torrid violence, with rioters torching shops and turning on residents including Han Chinese and Hui Muslims. Many Tibetans see Hans as intruders threatening their culture.
At least 19 people died in the unrest, which sparked waves of protests across Tibetan areas ahead of the 2008 Beijing Olympics.
Pro-Tibet groups abroad say more than 200 Tibetans have died in a subsequent crackdown across the region. Beijing has denied that and said it used minimal force.
Last year there were some fresh outbreaks of violence, but this year the area appears to have been largely quiet.
Rights groups warn that Beijing's heavy-handed response to the unrest, and the extra security forces it has poured into the region to keep the peace, cannot not bring lasting calm.
"Further repression will breed precisely the kind of instability the Chinese government fears," said Sophie Richardson, Asia advocacy director at Human Rights Watch.
"Addressing underlying grievances and allowing Tibetans to enjoy basic rights of expression, assembly, and due process is the only way to ensure the 'harmony' Beijing so craves."
(Additional reporting by Yu Le; Editing by Ben Blanchard)