Fighting broke out between police and a large group of Muslims in northwestern China after authorities demolished a mosque.
The incident happened in the city of Hexi, in the Ningxia region, on December 30 when several hundred of the Muslim minority Hui people tried to stop some 1,000 police from destroying the mosque. Officials had declared it to be an "illegal religious place."
The Hong Kong-based Information Center for Human Rights and Democracy said at least 50 people were injured and more than 100 detained.
There are reports two people were killed in the clashes but Chinese authorities deny there were any deaths.
Police finished demolishing the mosque after the clash ended.
The Hui are a mixture of peoples from the area that is now western China and include Turkic, Arab, and Han peoples, among others. They are considered an ethnic minority though they are one of the few Mandarin-speaking Muslim peoples, unlike the Turkic Uyghurs of the Xinjiang Autonomous Uyghur Region.
Incidents of violence involving the Hui are rare, whereas some Uyghurs continue to resist Chinese rule.
Last week Chinese police said they shot dead seven Uyghurs near Hotan during a hostage-rescue operation. Uyghur freedom groups outside China, while confirming the deaths, say police shot at Uyghur protesters.
compiled from agency reports