Mexico City, Muharram 28, 1436, Nov 21, 2014, SPA -- Police arrested 31 people for violent acts in during the largely peaceful demonstrations in Mexico City for justice over the fate of 43 missing students, dpa cited the authorities as saying on Friday. The demonstrations late Thursday, which were led by relatives of the missing students from Ayotzinapa teacher's training college, brought together 30,000 people. Masked youths committed acts of violence first near Mexico City's international airport, and later before the National Palace, the seat of the Mexican government, despite calls from speakers to remain peaceful. -- SPA 19:55 LOCAL TIME 16:55 GMT www.spa.gov.sa/w