With some Tibetans pushing harder against Chinese rule, the communist government is working to pacify the area.
The show of force Monday was meant to deter unrest while a local court sentenced a group of Tibetans for taking part in large anti-government protests in March in Xiahe, a town abutting a sprawling complex of golden-roofed temples.
Though the verdicts were not announced, the trial seemed timed to answer the complaints of the Dalai Lama and other exiled leaders meeting in India over the weekend that Tibetans' patience with China's domination was thinning.
Seven months after Tibetans across western China took part in the largest uprising against Chinese rule in nearly 50 years, the authoritarian government is adjusting tactics. Police checkpoints and guard posts in place for months are suddenly dismantled, only to reappear without warning days later.
Monday's police action came after several weeks in which riot squads had rarely been seen on the streets, residents said.
On high-altitude grasslands 90 miles to the south, the 200-year-old Xicang monastery, site of a violent demonstration in March, was open again for visitors. Clerics finished leading Sunday midday teachings in the main hall and immediately shuffled to another meeting -- a rollout of a new government-ordered study session.
Such campaigns -- which stress religion must not veer into political action -- have been used to keep the clergy in line.
Beijing maintains the Dalai Lama is promoting secession, not reconciliation, and that the government is bringing economic development to an impoverished area, while preserving Tibet's culture and religion.
But the communist leadership's heavy hand over Tibet and disregard for the Dalai Lama is adding to the gloom of Tibetans in China and in exile.
Though they number only 5 million, Tibetans are spread across a quarter of China and remain loyal to the Dalai Lama, a popular international figure who gives their cause a global impact.
After the weeklong meeting called to discuss a so-far failed policy of rapprochement with China after 50 years in exile, the Dalai Lama and other exiled leaders said they would maintain their push for genuine autonomy with China.
But the Dalai Lama struck a pessimistic note, calling the next 20 years a period of "great danger" for Tibet -- a seeming reference to Tibetans' ability to persevere and, at 73, his ability to live on and remain a rallying point.
"Tibet's traditions and culture are weakening rapidly. Can the exiles survive for another 20 years if their policies fail and if the Chinese government continues to resist a compromise?" asked Wang Lixiong, a Chinese writer and convert to Tibetan Buddhism who lives in Beijing.
"The current Chinese government is not going to solve the Tibet problem. Under one-party rule, power is crucial, and they are the power-holders."
The region around Xiahe -- pronounced SHAH-HUH -- stands as a gateway between the more fertile plains where Han Chinese and Hui Chinese Muslims farm, and the mountains and upland plateaus that are home to Tibetans. Off and on for centuries it straddled a fuzzy line of control.
In the days since the Dalai Lama called the extraordinary meeting on Tibet's future, Beijing has gone out of its way to display its commanding position in the tug-of-war. A senior Chinese official rejected a proposal this month to incorporate Xiahe and other Tibetan lands in one autonomous Tibet region governed by Lhasa but still part of China.
As the talks in India went on, China started a series of trials of Tibetans who took part in the March rebellion. In Luqu, a town of 7,000 where monks from Xicang tossed stones at local government offices, the court sentenced four people last week, a court officer said, refusing to disclose the verdicts.
The police action in Xiahe quieted the town as cars were cleared from the streets and people hurried past armed guards. Residents said they did not know what was happening.
A court officer confirmed those on trial participated in the March demonstrations, in which hundreds of monks marched through town, but declined to specify the number of defendants or their sentences.
Foreign visitors have been barred from the region for much of the past seven months, as authorities scoured monasteries and communities for uprising participants, detaining undisclosed numbers. A month ago the prohibition was lifted in Xiahe even as many other Tibetan areas remain closed.
Across the Xiahe region, Tibetans displayed robust devotion to the Dalai Lama and a strong resentment of the security China has imposed.
In Hezuo, a city set in the folds of a valley, Tibetans congregated around the towering 14-story fortress-like temple to a Tibetan saint. Many worshippers were under 50, having lived their entire lives under Communist Party rule.
At a prayer hall, two portraits of the Dalai Lama -- always discouraged and sometimes outright banned by the government -- were tacked to a shrine cluttered with reliquaries, paintings and photos of other revered teachers.