Monrovia - Liberians turned out in force on Tuesday to choose a successor to President Ellen Johnson Sirleaf, in a contest set to complete the country's first democratic transition of power in more than 70 years.Queues of people snaked through the streets of the capital Monrovia as voters waited patiently to cast their ballot, capping a campaign hailed for vibrant and violence-free debates and rallies.The vote is crucial test of Liberia's stability. Sirleaf, Africa's first female elected head of state, is stepping down after a maximum two six-year terms in which she steered the country away from the trauma of civil war, but, say critics, failed to tackle its poverty.The country's 2.18 million registered voters are choosing from a crowded field of 20 presidential candidates - although just one of them is a woman - and will also elect 73 seats in the lower chamber, the House of Representatives. Frontrunners include incumbent Vice President Joseph Boakai, who hailed the turnout as he cast his vote close to his home residence in Paynesville, a Monrovia suburb."I am satisfied that Liberians have turned out in large numbers to elect their leader. Whatever the result, I will accept it," Boakai said.Back-to-back civil wars, the 2014-16 Ebola crisis and slumped commodity prices have left Liberia among the world's poorest nations, while corruption remains entrenched.The ghosts of Liberia's bloody past are hard to avoid in this election.'New breed of leaders' The first official results are expected within 48 hours after voting closed at 18:00 (18:00 GMT). If no candidate wins 50% of the presidential vote, then a run-off of the top two contenders will be held on November 7 - an outcome analysts say is a near certainty."Don't vote because of tribalism or religion or all of that. Vote who you think has the capability, has the means to build on my legacy," Sirleaf said after casting her own ballot.Martin Saylee, a 28-year-old sociology student and a Boakai voter, told AFP while waiting to cast his ballot at the University of Liberia that the vice president could deliver job creation."Boakai is the most qualified. He is the one I believe will take this country to another level," Saylee told AFP.Close scrutiny Regardless of the result, the international community is keen to see Liberia's history of coups, assassinations and exiled dictators shift to a more stable footing after 12 years of peace under Sirleaf.Hundreds of electoral observers are overseeing the process, from Liberian political parties, civil society groups, the regional body ECOWAS, the African Union, the European Union and the United States."This is going to be one of the most observed elections we have seen," Jordan Ryan, vice president of the Carter Centre, an NGO founded by former US president Jimmy Carter, told AFP.