Quito — Supporters of Ecuadorean opposition leader Guillermo Lasso gathered in the streets for a second night to protest what they consider fraud at the ballot box that tilted a presidential runoff in favour of his leftist rival.Sunday's razor-thin election win by ruling party candidate Lenin Moreno bucked the trend of right-wing electoral victories in South America following 15 years of leftist domination.Even as calls from Latin American governments congratulating Moreno poured in, Lasso, a conservative banker, vowed to keep up the fight against the installation of an "illegitimate" government."We're not afraid of the miserable cowards who are on the wrong side of history," he told a crowd of a few thousand supporters outside the National Electoral Council in Quito.By nightfall, many supporters went home but a few hundred die-hards, some with children in tow, remained in a peaceful vigil. A line of riot police looked on.The scene was much calmer than the one on election night, when thousands of outraged Lasso supporters shouting "fraud" crashed through metal barricades to almost reach the entrance of the electoral council's headquarters in Quito.Scuffles also broke out in Guayaquil, where tear gas was fired to break up the crowd.With more than 99% of polling places counted, Moreno had 51% of the vote while Lasso stood at just under 49%.'An unprecedented situation'Key to Lasso's challenge of the results in all of Ecuador's 24 provinces were three exit polls that showed him winning. One by pollster Cedatos, which accurately predicted the results of the first round, gave him a victory by six percentage points.Part of the problem is the opposition's distrust of the National Electoral Council, which it says has become an appendage of the executive in the way the electoral board in Venezuela has all but lost independence under President Nicolas Maduro, a key ally of Correa."We're looking at an unprecedented situation: those behind the fraud are the judges themselves," Lasso told foreign reporters, adding that his campaign would seek a recount once the results are certified. "We expect they'll deny our requests but in doing so they'll be confirming the fraud."Despite such heated rhetoric Lasso so far has failed to present any evidence of vote tampering except for a single voting act of 248 ballots from a rural area whose tally is says was reversed in favour of Moreno when official results were computed.The Organisation of American States said its mission of electoral observers that visited at random 480 voting centres nationwide found no discrepancies between the tallies and the official results and encouraged Lasso to issue complaints through institutional channels.Correa accused Lasso supporters of trying to deny the results and provoke violence. On Monday, he sent a flurry of tweets saying the Lasso campaign had hired Cedatos."By force they want to achieve what they can't at the ballot box," he said.He also appeared alongside Moreno at changing of the guard ceremony at the presidential palace. Before a crowd of hundreds of supporters, the apparent President-elect sang "happy birthday" to Correa, who turns 54 later this week.'Citizens' Revolution'For weeks Ecuadoreans polarised by 10 years of Correa's iron-fisted rule had been bracing for a contested vote.With Ecuador's economy slated to shrink by 2.7% this year as oil prices remain low, analysts had been anticipating that Lasso would rally support from the 60% of voters who backed anti-Correa candidates in the first round and join the growing list of Latin American nations — Argentina, Brazil, Peru and Venezuela — shifting to the right in recent elections.The majority of voters also said they were hungry for change amid ongoing corruption allegations related to bribes that Brazilian construction giant Odebrecht paid to officials in Correa's government and a $12m contracting scandal at state-run PetroEcuador.Yet in the final weeks of the race, Moreno inched ahead in polls amid an aggressive campaign led by Correa to cast Lasso as a wealthy, out-of-touch politician who profited from the country's 1999 banking crisis. Moreno, 64, also benefited from last-minute doubts that the pro-business Lasso, if elected, would gut social programmes that have endeared poor voters to Correa's "Citizens' Revolution".Outside the region, the election was being closely watched by supporters of WikiLeaks founder Julian Assange, who has been living under asylum at Ecuador's embassy in London since 2012.Before the election, Lasso had said he would evict the Australian activist, who is wanted for extradition by Sweden, within 30 days of taking office. Moreno said he would allow him to stay.On his Twitter account shortly after the results became known, Assange took a jab at Lasso's pledge."I cordially invite Lasso to leave Ecuador within 30 days (with or without his tax haven millions)," he wrote.