Chinese authorities sealed off a town in northwestern Xinjiang region, and paramilitary police patrolled the streets after at least 10 people were killed in a separatist riot last week, residents said. "No one can leave, no one can enter," one resident said by telephone from Yining, a mostly Muslim town near the border with Kazakhstan. Authorities earlier had closed the airport and railway station and imposed an after-dark curfew, residents said. At least 10 people were killed, although one exile group claimed that as many as 300 had died. Police blamed the rioting on a banned Islamic sect; a separatist group said the fighting was ignited by the public execution of 30 young Muslims.