China on Tuesday told the new United Nations (UN) human rights chief to respect its sovereignty after she called for access to its regions following “deeply disturbing” allegations of mass detentions of Muslim minorities.

Michelle Bachelet decried China's ongoing crackdown on the mostly Muslim Uighur minority in her first remarks as head of the UN rights watchdog in Geneva on Monday.

“China urges the UN High Commissioner for Human Rights and its office to strictly abide by the mission and principles of the UN Charter to respect China's sovereignty,” said foreign ministry spokesman Geng Shuang.

China has long imposed draconian restrictions on the lives of Muslim minorities in its Xinjiang region in the name of combating terrorism and separatism, with police measures intensifying in recent years.

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Upwards of one million ethnic Uighurs and other Turkic Muslim minorities are being held in counter-extremism centres, according to estimates cited by a UN panel on racial discrimination last month.

Bachelet cited the work of the UN experts noting the “deeply disturbing allegations of large-scale arbitrary detentions of Uighurs and other Muslim communities in so-called re-education camps across Xinjiang”.

She called on Beijing to permit the UN rights office access to “all regions” of China and embark on a discussion of the issues.

In Beijing, the foreign ministry did not reject the request outright but told the UN rights chief and her office to “fulfil their responsibilities in a just and fair way instead of listening to only one side”, without elaborating further.

Last month a Chinese official said the tough security measures in Xinjiang were necessary to combat extremism and terrorism but did not target any specific ethnic group or restrict religious freedoms.