Washington - The United States on Tuesday urged Chinese authorities to release a dozen human rights and religious freedom defenders detained during a recent visit by a top US diplomat.
International religious freedom envoy David Saperstein said the activists - including respected human rights lawyer Zhang Kai, pastors and other Christian militants - were held during his August 20-28 trip to China.
"More broadly, these detentions fit into the disturbing pattern of state intimidation of public interest lawyers, Internet activists, journalists, religious leaders," Saperstein told reporters.
"They clearly underscore the precariousness of religious life in China."
Saperstein decried the "correlation" between the fact that Zhang had gathered the group to meet with him and that they were all detained the night before the meeting was due to happen.
"There were other incidents involving people who met with us who were detained as well," the US diplomat added.
"It is a source of great concern to us and we are calling on the government to immediately release all these human rights activists and religious leaders."
In July, rights groups had denounced what they termed China's unprecedented crackdown, with dozens of human rights lawyers including Zhang arrested.
Since President Xi Jinping came to power in 2013, the government has taken a harder line toward civil society and religion.
In the eastern province of Zhejiang, authorities have stepped up a long-running campaign to remove church crosses. Several Catholic and Protestant churches were destroyed.
The United States has increased warnings to China on the thorny issue of human rights and religious freedom that could be at the heart of talks between Xi and US President Barack Obama during the Chinese leader's upcoming state visit to the White House.