Chinese officials have pushed back against growing criticism of the detention of Muslim minorities in internment camps, claiming authorities are merely providing professional training and education.

Beijing is facing allegations of mass incarceration and repression of Uighurs, Kazakhs and other ethnic minorities in Xinjiang in China’s north-west. An estimated 1.1 million people have been placed in internment camps, including re-education camps where, according to former detainees and other witnesses, inmates are subjected to intense political indoctrination and abuse.

“It is not mistreatment,” Li Xiaojun, the director for publicity at the Bureau of Human Rights Affairs of the State Council Information Office, told reporters on Thursday, according to Reuters. “What China is doing is to establish professional training centres – educational centres.”

Li added: “If you do not say it’s the best way, maybe it’s the necessary way to deal with Islamic or religious extremism, because the west has failed in doing so. Look at Belgium, look at Paris, look at some other European countries. You have failed.”

China’s restrictive policies in Xinjiang, part of a “strike hard” campaign to counter terrorism after riots by ethnic people in 2009, has come under increasing scrutiny as media reports, witness accounts and documentation of the camps accumulate. China denies any camps are used for political indoctrination.

Two former detainees of a re-education camp told the Guardian they were forced to learn Mandarin Chinese, sing patriotic songs, and study Chinese Communist party doctrine. Both said they were not taught any vocational skills.

Conditions in re-education facilities and other internment camps have been described as inhumane. One former detainee said he was forced to wear “iron clothes”, an outfit of metal claws and rods that left him immobile, for 12 hours as punishment for disobeying a guard. An ex-detainee of a women’s detention centre told the Guardian she witnessed a woman having her feet and hands chained together for four days.

According to a Human Rights Watch (HRW) report on Monday, former detainees described being denied food, being shackled or forced to stand for 24 hours, and being subjected to solitary confinement and sleep deprivation.

The UN has called on China to release all those arbitrarily detained while the US government is reportedly considering sanctions against Chinese officials and companies involved in the construction of the camps.

As global attention to Xinjiang has grown, China’s response has shifted from blanket denial to justification. On Monday, Geng Shuang, a foreign ministry spokesman, said in response to the HRW report: “The series of measures implemented in Xinjiang are meant to improve stability, development, solidarity and ... crack down on ethnic separatist activities and violent and terrorist crimes.”

At a UN panel last month, Hu Lianhe, a representative for the Chinese delegation, said there was “no such thing as re-education centres in Xinjiang”, but went on to describe vocational centres.

“For those who are convicted of minor offences, we help and teach them in vocational skills in education and training centres, according to relevant laws. There is no arbitrary detention and torture,” he said.