Many Muslims in China’s restive province of Xinjiang are being prevented from celebrating Ramadan because of an increased security clampdown, according to a Beijing-based Uighur activist and a human rights group.

The Muslim world began celebrating the holy month last week but, activists say, ethnic Uighurs in the western province are being stopped from fully participating in the festivities after violent clashes in the region in June left more than 37 people dead. The government imposed a major security clampdown on the region after the violence, the worst since large-scale unrest in 2009, that killed more than 200 across the province.

According to Ilham Tohti, a Uighur academic at Minzu University of China in Beijing, Uighur families are being increasingly monitored by security forces and threatened with arrest for congregating in mosques or homes during Ramadan.