Over 40 countries are pressing China to give the UN immediate access to Xinjiang Province to look into reports that more than a million people, mostly Muslims of the Uighur ethnic group, are being unlawfully detained there.
The joint statement, read Tuesday by Canada's Ambassador to the UN, spoke of Uighur Muslims also being subject to torture and forced labor.
The UN High Commissioner has been trying to negotiate access since 2018.
China has dismissed those efforts, calling them politically motivated.
A senior Chinese diplomat told the UN Human Rights Council that Beijing would welcome a visit, but not one based on what he called "a presumption of guilt."