Several protesters were taken away by police while a number of injured were taken to hospital in ambulances, a Reuters reporter said.
The protest started on Monday, when about 5,000 demonstrators marched to the presidential headquarters but were stopped by riot police and began a sit-in protest, blocking traffic on a central boulevard. Police asked demonstrators to leave the road but they refused.
The protest, which was organised by young activists with no affiliation to any political parties, was triggered by the state regulatory commission's decision last week to increase the tariff on electricity by 17 to 22 percent from Aug. 1.