Monrovia - Liberia's Supreme Court on Friday began hearings of an appeal filed by two political parties claiming fraud in the first round of the presidential election and calling for a re-run of the vote."We remain optimistic till the final ruling is given. This is the rule of law and the Supreme Court is the final decision-making body." Darius Dillon, a leader of the Liberty party, told journalists.Liberty's veteran opposition leader Charles Brumskine along with incumbent Vice President Joseph Boakai of the Unity party brought the demand to Liberia's top court on Monday after the country's electoral commission ruled that irregularities recorded during voting did not affect the overall result.Legal documents filed by the parties alleged that there were errors linked to the voter register and ballot paper serial numbers.The filing also claimed that "the pervasiveness of the fraud and gross irregularities throughout the electoral process warrant a re-run of the elections" - an unprecedented demand to start the entire process of choosing a new president from scratch.The Supreme Court said in a statement it would "conduct the final hearings between the Liberty party and the Unity party on one hand and the Election commission on the other hand." A ruling is expected by Thursday, it said.The October 10 first round vote was held to replace President Ellen Johnson Sirleaf, a Nobel Peace Laureate and Africa's first elected female leader who is stepping down after a constitutional maximum of two six-year terms.Boakai was due to face the top-placing candidate - former international footballer George Weah - in a runoff on November 7, but the Supreme Court put a temporary stay on the poll while the National Elections Commission (NEC) heard the complaints of the parties that came in second and third.The NEC found the parties' allegations either unfounded or exaggerated and ruled last week it had not carried out a fraudulent election, a decision maintained upon appeal.Battered by back-to-back civil wars between 1989 and 2003 and an Ebola crisis that killed thousands from 2014 to 2016, the election is considered a crucial test of the west African nation's stability and would be the first smooth transition of power since 1944.