BEIJING - Anti-terror efforts in controversial “reeducation centres” in China’s Xinjiang region will be governed by new standardised rules, as international criticism mounts over the detention of as many one million in the restive far west.

The revised rules, passed Tuesday, call on local governments to tackle terrorism by establishing “vocational education centres” that will carry out the “educational transformation of people who have been influenced by extremism.”

The centres should teach Mandarin Chinese, legal concepts and vocational training, and carry out “thought education,” according to a copy of the rules posted on the regional government’s web site. As many as a million people are believed to have been detained in extra-judicial detention centres in Xinjiang as authorities there seek to battle what they describe as religious extremism, separatism and terrorism.

A previous version of the rules issued in March 2017 included a long list of prohibitions on religious behaviour including wearing long beards and veils.

It also encouraged local governments to engage in “educational transformation”, a term critics have described as a euphemism for brainwashing.

The detentions have mostly focused on the region’s Muslim minorities, especially the Uighurs, a Turkic ethnic group that make up around half of Xinjiang’s population of 22 million.

The new regulations seem aimed at standardising the centres’ management, which was initially carried out piecemeal.

Beijing has denied reports of the mass detention of its citizens in camps but evidence is mounting in the form of government documents and testimonies from former detainees.

Chinese authorities have, however, said that they give vocational and language training to people guilty of minor crimes.

Testimony from people who have escaped the centres provides a much darker picture, however.

In July, a former teacher at one of the centres told a court in Kazakhstan that “in China they call it a political camp but really it was a prison in the mountains.”

The announcement comes as Communist Party leaders in Urumqi, the regional capital, on Monday led cadres in swearing an oath to fight the “pan-halal trend”.

Halal - Arabic for “permissible” - refers to a set of rules guiding Muslims on what is allowed according to the religion. It is frequently applied to food and drinks but also includes other personal hygiene products like toothpaste and cosmetics.

Authorities in Xinjiang have long seen the expansion of the term to include non-food items as a sign of religious extremism.