The United States is demanding that China release a well-known Christian lawyer and religious figures detained last month ahead of a meeting with a visiting senior U.S. diplomat.

David Saperstein, the U.S. ambassador at-large for religious freedom, said the detentions of attorney Zhang Kai and the others were a "particularly alarming development" as it came while he was in China preparing to meet the group. Saperstein said there was "no excuse" for the detentions, particularly as Chinese authorities had encouraged his August 20-28 visit to take stock of religious freedom in the country. Saperstein called on authorities to release the detainees, who he said had been accused of threatening public order.

Zhang has been advising churches in China's Zhejiang province that are resisting orders to remove crosses from church roofs.