Bolivia's electoral authorities on Saturday started delivering the sealed ballots ahead of Sunday's presidential election that will end the interim mandate of President Jeanine Anez.

Ballots in Bolivia were guarded by police and army officers, who will remain with the electoral material until Sunday. There are over 7.3 million Bolivians eligible to vote on Sunday to pick up for new president, vice president, senators, deputies, and others for the period of 2020-2025.

"They are been expected in the election points where they will be safe. These (election) packages are going to be received in those points, logged and guarded," said Luis Vilca, an official for the Bolivian Electoral Tribunal. 

The leading contenders for the presidency are former Economy Minister Luis Arce and former President Carlos Mesa, a centrist historian and journalist. To avoid a second round, the election winner requires at least 40 percent of valid votes in the first round and a 10-point advantage over the closest competitor.

The electoral tribunal announced on Saturday that the upcoming elections will be monitored by 213,600 citizen observers. Special election observation missions are also expected from a dozen international organizations, such as the EU, the Organization of American States and the UN, as well as several Bolivian civic organizations. In the days leading up to the vote several international observers had arrived in the Bolivian capital to ensure the execution of fair elections.

The vote will be key to the direction of the landlocked country after a ballot last year prompted ousted President Evo Morales' resignation and plunged the Andean country into turmoil. However, it is reported that Bolivians in wealthier areas of the capital city of La Paz have begun stocking up on essential supplies and queuing up to buy gas ahead of the election, fearing a return of deadly clashes.

The incumbent president Anez took office in November 2019 after the long-term leftist leader Evo Morales resigned the presidency and went into exile when police and army withdrew their support of him. Anez then announced her job as interim president would be to convoke elections to replace Morales. On that November, Bolivia had seen weeks of protests and turmoil where people claimed fraud over the reelection of Morales, who governed for nearly 14 years.

While Morales was barred to participate into the elections for the presidency or the senate followed his ouster, he chose Arce as his stand-in for the Movement To Socialism party. The party's backing depends heavily on working-class and rural voters who remain loyal to Morales.

(With input from agencies)