Protests against capitalism accompanied the opening of the G-20 summit.Demonstrators threw rocks and smashed store windows in Pittsburgh about 1.5 kilometers from the fenced-off convention center where the summit is taking place. Police in body armour and carrying plastic shields threw pepper gas canisters to disperse the mostly young protesters. The police used bullhorns to warn demonstrators that they’d use gas and other non-lethal force if necessary. The marchers overturned dumpsters and hurled objects at the officers chasing them. The clashes lasted for about four hours after police dispersed some 2,000 people who had gathered for a march. A series of actions are planned for later today at various locations in the city.