A demonstrator is hit by a jet of water released from a riot police vehicle during a student rally against the government's public education system in Santiago city Sept 22, 2011. [Photo/Agencies]

Riot police detain a student during a protest against the government to demand changes in the public state education system in Valparaiso city, about 121 km (75 miles) northwest of Santiago, Sept 22, 2011. [Photo/Agencies]