Election officials in Liberia warned against any attempt to disrupt tallying on Wednesday after the UN hailed a "smooth" voting day in the war-scarred west African country's hotly-contested polls.
The National Elections Commission (NEC) said the first results of Liberia's second post-war polls were due on Thursday, with newly Nobel-crowned incumbent Ellen Johnson Sirleaf facing a stiff challenge from former diplomat Winston Tubman.
"Any unauthorised person that attempts to disrupt or interfere with the sorting and counting at polling places will be arrested and prosecuted in accordance with the law," said NEC chief James Fromayan.
Sirleaf was jointly awarded the Nobel Peace Prize just days before Tuesday's vote, for her work in rebuilding the country and promoting women's rights after a savage 14-year war in which some 250,000 people were killed.
She faces stiff opposition from Tubman, 70, a Harvard-trained lawyer and nephew of the country's longest serving president William Tubman, who has said she does not deserve the prize.
Tubman, who has called Sirleaf out on failed reconciliation efforts and shady ties to warlord-turned-president Charles Taylor, says not much has changed for the average Liberian in a country where unemployment is around 80 percent.
But Sirleaf wants more time to continue rebuilding the "broken country," whose fragile democracy is facing a key test in the election, the first organised by Liberians themselves.
The 8,000-strong UN mission in Liberia is providing security back-up as the country prepares for the announcement of results, which has often proved to be the most edgy moment in recent African elections.
"We are still working on security with the Liberia National Police to ensure that the rest of the process goes smoothly," UNMIL spokeswoman Yasmina Bouziane told AFP.
UN chief Ban Ki-moon welcomed "the smooth holding of the presidential and legislative elections in Liberia."
"He commends the people of Liberia for exercising their right to vote in a calm and peaceful manner," said his spokesman. "This election is an important milestone in the efforts to consolidate peace and democracy in the country."
"The Secretary-General calls on the people of Liberia, and all parties and candidates, to preserve the existing peaceful atmosphere as the tallying of votes gets underway.”
Fromayan said the incident-free vote showed the country had matured to reach "a new dimension where the Liberian people chose the ballot box over the barrel of a gun."
An impressive turnout from some 1.8 million eligible voters was expected as hundreds were seen lining up under the blazing sun in some parts of the country, and thunderous rainfall in the capital.
African Union observer mission chief Speciosa Wangira-Kazibwe said voting in the presidential, senatorial and legislative elections had proceeded "very well."
She said the turnout "puts a big challenge on the leaders that are being elected today. When you look in the eyes of these Liberians they are saying we are giving you our vote, and you will lead us to prosperity."
Observers warn that the peace is still fragile as victims of a war fought by numerous rebel factions, some using drugged-up child soldiers, maiming, raping and terrorising citizens, had yet to experience reconciliation.
Sirleaf has been criticised for dragging her feet in implementing recommendations by a Truth and Reconciliation Commission which names her on a list of people who should be barred from public office for backing warlord-turned-president Charles Taylor.
Candidates for presidency, 15 senatorial seats and 73 legislative seats will have to sweep an absolute majority to avoid an eventual run-off on 8 November.