The group has recently been instigating unrest via the Internet and by other means calling on the rioters "to be braver" and "to do something big."
The Xinjiang regional government says terrorism, separatism and extremism... are behind the violence.
The Xinjiang regional government also says instigators began spreading information on the Internet on Saturday evening, calling for a demonstration in Urumqi.
And they say, on Sunday Rebiya called on her accomplices in the country to further incite unrest.
Regional government authorities say the situation is now under control.
Regional government authorities say police have arrested several hundred participants, including more than ten key figures who fanned the unrest. Police say they are still searching for about 90 other key figures behind the unrest.
