GENEVA (Reuters) - United Nations rights boss Michelle Bachelet called on China on Thursday to provide "unfettered access for an advance team" to prepare her proposed visit, saying it should include a probe into the situation of the Uighur minority.

Bachelet's speech to the U.N. Human Rights Council followed remarks a day before by China's ambassador, Chen Xu, who told the forum that his country was looking forward to her visit, including to Xinjiang this year.

U.N. experts and activists say at least 1 million ethnic Uighurs and other Muslims are held in detention centres in Xinjiang. China describes them as training centres helping to stamp out terrorism and extremism and give people new skills.