Student organizers at the last minute decided against marching downtown to avoid a confrontation with security forces in the government-controlled district.
Instead they concentrated in the wealthier, eastern neighborhoods that have been the hotbed of unrest since February.
Demonstrators carried signs on yesterday blasting a Supreme Court ruling this week that gives police the right to disperse protests that don't have a permit.
Opponents say the ruling is the latest attempt by the socialist government to muzzle dissent amid widespread discontent with runaway inflation and record shortages.