The protesters, mostly from the Shi’ite Muslim majority in the Sunni Muslim-ruled Gulf Arab state, advanced about 2 km (1.5 mile) before police forces were able to stop them by firing tear gas, a Reuters witness said.
Traffic came to a standstill on the highway, the main thoroughfare into the capital of the regional banking hub.
Protesters fled into nearby Shi’ite villages to regroup and march back to confront lines of riot police.
Sheikh Ali Salman, leader of the largest Shi’ite opposition group Wefaq, had earlier called on youths to eschew violence in protests after clashes with police escalated in recent weeks, with teenagers throwing petrol bombs and iron bars.
Inspired by uprisings in Egypt and Tunisia , Bahrainis — mainly from the Shi’ite majority — took to the streets on February 14, 2011 to demand democratic reforms. But the Sunni Muslim-led government crushed the protests a month later after talks involving Wefaq went nowhere and sectarian violence spread.
Wefaq and other opposition parties, including the secular Waad, want constitutional changes that would give the elected chamber of parliament the authority to form governments.
The government, dominated by the Sunni Al Khalifa family, has given parliament extra powers of scrutiny over ministers and budgets but not moved on the bigger opposition demands.
The Western-allied Arab state has geo-political importance as home to the U.S. Fifth Fleet, and it is a key ally of Saudi Arabia , the world’s top oil exporter, which faces sporadic Shi’ite unrest in its eastern, crude-producing region.