GENEVA — United Nations human rights officials have sharply condemned regulations issued by China that seek to provide a legal basis for the mass internment of Muslims in the Xinjiang region.

Six United Nations officials and rights experts said in a letter sent on Monday to the Chinese government that the regulations were a violation of international law, and they urged that those responsible be held accountable.

The regulations were issued by the authorities in Xinjiang in western China, who said they were intended “to contain and eradicate” extremism.

The United Nations experts contended that the new rules to justify mass internments in “re-education centers’’ were based on overly broad definitions of extremist behavior and amounted to criminalizing the legitimate exercise of basic rights.