GENEVA (Reuters) - The United Nations human rights office told Reuters on Tuesday that it had received reports alleging that a number of Chinese citizens had been detained or threatened ahead of the 30th anniversary of the Tiananmen Square crackdown.

Spokeswoman Ravina Shamdasani said that it also had received reports of “increased censorship” of the mention of the Tiananmen anniversary and was calling on Chinese authorities to enhance freedom of peaceful assembly and expression.

“We have made our concerns known to the Chinese government and we are working to also verify these reports that we have received,” Shamdasani told Reuters Television.