The early election on Sunday is seen as a showdown between Vucic's right-wing Serbian Progressive Party (SNS) and the Students' List, a group that emerged from months of demonstrations triggered by a train station tragedy that killed 16 people in the country's north. The youth movement, blaming alleged corruption-fueled negligence during renovation work, has rattled Vucic more than any other challenge during his 12 years as both prime minister and president.
Belgrade residents lit flares and cheered as students arrived from various directions after walking through rural areas that are Vucic's traditional strongholds. Ilija Srdanovic, a physician running on the Students' List ticket, told N1 television that "this is incredible, this energy is unstoppable."
Vucic held a rally in the southern city of Nis in front of thousands of flag-waving supporters. The former president resigned in September to seek a return as prime minister. "There will be no more politics in schools and at faculties," Vucic vowed, repeating accusations that the students and their professors work under instructions from abroad to "breakdown" the country.
Both sides are said to be polling close, making the outcome uncertain and fueling fears of incidents if both declare victory. Authorities on Wednesday detained six people allegedly suspected of planning unrest on election day. Police have made similar arrests ahead of major protests in the past, which government critics say aim to intimidate protesters.
A report published Wednesday by the Serbian Center for Research, Transparency and Accountability cited a "narrowing of freedoms and deepening of inequality" among election participants and voters. It said opposition activists are being monitored and questioned and their communications intercepted, and noted a major discrepancy in mainstream media coverage in favor of Vucic and over 100 violent incidents during the campaign. International election monitors and the European Union have expressed concern about the ballot's safety and fairness following widespread irregularities in the past.