The new regulations require all residents to hand over their travel documents and then apply to get them back if they wish to travel overseas. The state-run Global Times newspaper said the policy was designed to "maintain social order" amid the rising spectre of terrorism in the region.

The Chinese government has blamed the rise of radical Islam among Uighurs for a series of deadly attacks in mainland China in recent years, most notably a mass stabbing in Kunming in 2014.

Uighurs – a Turkic-speaking Muslim ethnic minority whose culture and language sets them apart  from China's majority Han population – in turn say China's repressive rule is responsible for the unrest.

Beijing has increasingly grappled with what it says are significant numbers of Uighurs travelling to Syria to fight with Islamic State. In September, Kyrgyzstan state security officials said Syrian-based Uighur militants were behind a suicide bombing at the Chinese embassy in Bishkek at the end of August.

Violence has continued to flare particularly in the more remote southern regions of Xinjiang, though accounts are difficult to independently verify and Chinese state-run media have been instructed not to draw attention to the unrest.

The passport restrictions, however, represent a reversal of recent moves to streamline the issuing of travel documents to Xinjiang residents.

In March, Che Jun, then deputy Xinjiang party secretary, said authorities should not "try to save a little only to lose a lot" by restricting the movements of all Xinjiang residents due to a "small number" of "criminal, radical and terrorist elements".

The apparent change of heart coincides with the appointment of new Xinjiang party secretary Chen Quanguo in August.

Local police in Xinjiang's city of Shihezi confirmed to Fairfax Media that residents had to turn in their passports by February. "This is a Xinjiang-wide policy," said an officer, who declined to give her name.

Human Rights Watch, an international non-governmental organisation, said it had confirmed the policy in various other locations across Xinjiang, thought it had not yet come into force in the region's capital, Urumqi.

"Chinese authorities have given no credible reason for taking away people's passports, violating their right to freedom of movement," said Sophie Richardson, China director of Human Rights Watch. "Doing so across an entire region is a form of collective punishment and fuels resentment toward the government in a region where tensions are high."