The use of social networks is growing in Mexico, but the country had largely escaped the kind of rapidly formed, fast-moving youth mobs seen in Europe and the United States before the outbreak of violence in the capital Sunday.
Mexico City police chief Manuel Mondragon said two young men had called on other people to gather for a concert of reggaeton music on Sunday, but hundreds more people showed up than could fit into the bar where it was being held.
Mondragon as many as 600 angry youths who couldn't get in to the concert went on a rampage at local subway stations, damaging turnstiles and streetlamps, robbing people and tossing fireworks in an area popular among foreign residents and tourists. A police car had its windshield smashed.
Dozens of riot police swarmed into an upscale shopping mall to arrest some of the youths, causing some stores to temporarily lock their doors.
Mondragon said the people taken into custody were mostly younger than 18.