Barricades were erected by anti-government demonstrators in Caracas on Monday, another mark of the worst unrest in Venezuela for 10 years.Thirteen people have so far died, mostly from gunshot wounds. Despite calls from president Nicolas Maduro for national dialogue as well as opposition leader Henrique Capriles urging peaceful demonstrations, there is no sign of a slowdown. The opposition, meanwhile, has rejected talks with Maduro and are demanding the release of those detained after protests.