Slovaks voted in an election Saturday that the leftist party of former premier Robert Fico was poised to win as an uprecendented corruption scandal took its toll on governing right-wing rivals. Anger over the so-called \"Gorilla\" graft revelations erupted on the capital\'s streets on the eve of the poll, when rock-throwing protesters clashed with police who used teargas and detained 19 demonstrators. But protest organisers on Saturday complained that police had over-reacted and \"violated\" their constitutional rights during the clashes that left two people injured. Gorilla is the code-name for a source in a secret service wiretap report leaked online late last year that pointed to a web of shady connections between many centre-right politicians and a local financial group. In a nod to what the European Union could expect of him as prime minister, Fico meanwhile underscored Slovakia\'s \"duty to show solidarity toward EU\" as he voted in Bratislava. Economic woes are another factor in the election in the ex-communist nation of 5.4 million people, the eurozone\'s second poorest member, where unemployment is above 13 percent. Although growth this year is forecast at 1.1 percent, its export-driven economy makes the small nation vulnerable to the region\'s wider slump. Fico, 47, has sought to woo voters by vowing to improve social welfare, and to raise taxes for the rich and for top-earning businesses. Opinion polls showed his Smer social democrats tipped to win, and the SDKU-DS of outgoing Premier Iveta Radicova struggling with support that may fall as low as five percent, the threshold for parliamentary representation. The election is being held early after the centre-right government collapsed in October in a party dispute on whether Slovakia, which joined the eurozone in 2009, should pay into a European bailout fund. The issue on most voters\' minds Saturday was the Gorilla scandal that suggests parties in the 1998-2006 government of then premier Mikulas Dzurinda, now the ruling party leader, had corrupt ties with financial group Penta. Grigorij Meseznikov, a Bratislava-based analyst, told AFP Saturday the Gorilla scandal had \"lowered the credibility\" of politicians. Alzbeta Kezesova, a 70-year-old pensioner voting at a polling station in the capital Bratislava, told AFP she shared the frustrations of the younger Slovaks who had taken to the streets the night before. \"Corruption is the biggest problem in Slovakia,\" she said, adding that she had considered not voting at all. The next government \"should strip lawmakers of their immunity,\" she insisted. Another voter, chef Jozef Lison, 58, supported the left \"because they did more for the people while they were in power than the outgoing government\". Marian, a 24-year-old Bratislava university student, who declined to give his last name, said he and his group of friends had opted for new parties spawned by the anti-corruption movement in the hope of \"a slight chance for change.\" While the latest surveys said almost one third of voters remained undecided, most centre-right coalition parties faced the threat of being wiped out. Local media reported several voting incidents including illiterate members of the ethnic Roma minority allegedly being instructed to vote by number for Fico\'s Smer party. Outgoing prime minister Iveta Radicova -- a popular figure who quit politics before the Gorilla scandal broke -- pointed to the wider political malaise sweeping the European Union as the eurozone debt crisis stumps growth. \"In the past 20 months, ten governments collapsed in the European Union,\" she said as she voted near Bratislava. \"Today people are deciding not only how we will live next year but how to reboot the economy and define new rules of trust between politicians and voters.\"