Riot police fired tear gas, rubber bullets and swung batons Monday to disperse thousands of stone-throwing protesters in the Bangladeshi capital demanding electoral reforms and a postponement of this month's elections, witnesses and news reports said. About 5,000 protesters tried to overrun barbed-wire barricades manned by police, triggering the clashes in central Dhaka, leaving several people injured. The violence broke out on the second day of a crippling three-day transportation blockade imposed by a 19-party alliance that opposes the January 22 election. Streets were empty Monday apart from a few buses, three-wheel taxis and rickshaws that had defied the blockade to provide the only transport for the capital's 10 million residents. Clashes between alliance supporters and security forces also were reported in other parts of the capital city and its outskirts, where dozens were wounded and several activists were arrested, news reports said.