A Chinese government worker in the ancient Silk Road oasis of Kashgar beckons two women to her streetside stand and logs their details under the gaze of a surveillance camera. Their offence: wearing veils.

The "Project Beauty" campaign aims to discourage women from covering their faces — a religious practice for some Muslim Uighurs, the largest ethnic group in China's Xinjiang region — in an attempt to improve security.

But critics warn the effort could sow resentment and backfire instead.

"We need to hold onto our traditions and they should understand that," said a 25-year-old woman who has been registered twice.

Offenders were made to watch a film about the joys of exposing their faces, she added, speaking behind a white crocheted covering.

"The movie doesn't change a lot of people's minds," she said, like others declining to be named.

Xinjiang, a vast area bordering Pakistan and Central Asia in China's far west, beyond the furthest reaches of the Great Wall, has followed Islam for centuries.

It came under Chinese control most recently during the Qing dynasty in the late 1800s.

For years it has seen sporadic unrest by Uighurs which rights groups say is driven by cultural oppression and intrusive security measures but China attributes to extremist religion, terrorism and separatism.

Authorities' concerns intensified after a deadly attack in Beijing's Tiananmen Square last month which police blamed on Uighurs.

Kashgar residents say veil restrictions sparked at least one deadly conflict this year near the city, where 90 per cent of the area's 3.3 million residents are Uighur.

"For the Chinese government the causal process is: the Islamic extremists ask for independence, ask for separatism, then that's why they set very strict limits on Uighurs' religious activities," said Shan Wei, a political scientist at the National University of Singapore.

"For the Uighurs' part, it's: 'OK, I wasn't involved in any political movements, I'm not a separatist at all, but you set so many stupid restrictions on my daily religious activities that I hate you'," he added, pointing out that China's other Muslim minorities did not face such rules.

Unveiling resentment

Women in Kashgar sport a range of coverings, from bright scarves draped stylishly over hairdos that leave their necks exposed, to sombre Saudi-style black fabric cloaking all but their eyes.

Policies to stop them covering their faces, and to a lesser extent their hair, are not publicised. City authorities declined to comment and Xinjiang officials could not be reached.

But "Project Beauty" stands could be seen around the city, and a tailor said campaign staff had instructed him not to make the full-length robes often worn with face coverings.

Other residents said that to enter government offices, banks or courts, women had to remove their veils and men shave their beards, another Muslim practice.

In Hotan, another predominantly Uighur city 500 kilometres (310 miles) to the east, at least one hospital received government forms to report back on veiled patients.

A Xinjiang government web portal featuring Project Beauty did not mention banning veils but listed its goals as promoting local beauty products and other goods, and encouraging women to be "practitioners of modern culture".

The Xinjiang Daily, run by the ruling Communist Party, warned of the potential dangers of Islamic dress in a July opinion piece.

"Some people with ulterior motives are distorting religious teachings" and "inciting young people to do jihad", it said, adding that black robes induced depression and scared babies.

The ruling party has sought periodically to stamp out veiling since taking power in 1949, first launching an atheism drive and banning the headgear altogether in the 1960s and 70s, said Gardner Bovingdon, a Xinjiang expert at Indiana University Bloomington.

Restrictions relaxed in the 1980s as China opened up, but tightened again in the following decade after religiously tinged protests broke out.

A worker at a Project Beauty checkpoint cited "security" as a motive for the campaign.

Some Uighurs endorsed the authorities' precautions, saying thieves or suicide bombers might exploit the outfits to hide packages and their identity.

But they also argued that some officials' aggressive approach sparked resentment and violence, including an April attack by Uighurs on police in Maralbishi county outside Kashgar that left 21 people dead.

State media blamed "terrorists" who "regularly watched video clips advocating religious extremism".

A few Uighur residents said the "real reason" was that an official tried to force a woman to remove her veil and "people got upset".

"They should have explained slowly that wearing these things is not allowed, we know you are good guys but some criminals wear the veil and robe to do suicide bombs and other bad things," one said.

A Uighur metalworker complained that women taught from youth to veil found it hard to change, and that other Chinese Muslim men grew beards but only Uighurs were labelled terrorists.

Some women took a pragmatic view.

A 35-year-old bakery owner with a gauzy orange scarf wrapped around a bun said the need to unveil in government buildings did not overly bother her. Women were becoming less strict about veiling in any case, she said.

But others remove their face covers before approaching Project Beauty checkpoints to avoid trouble, said a 19-year-old woman from a jade-selling family.

The "Beauty" people were everywhere, she said.