Liberia's President Johnson-Sirleaf poised for re-election

AFP - Polling opened in Liberia's disputed presidential run-off Tuesday, the day after at least four opposition supporters were killed amid a boycott protest by the challenger.

Few people were voting in the capital Monrovia, in marked contrast to long lines which greeted the opening of the polls in the first round, won by incumbent president and joint Nobel Peace Prize laureate Ellen Johnson Sirleaf.

"I have come to vote but I am not happy for what happened yesterday, after all we are all Liberian and no one should be happy seeing other Liberians being killed," said Rita Queegbay, 39, one of only about 30 people at the Duport Road polling station.

Challenger Winston Tubman, a former UN diplomat, came second in the first round and urged his supporters not to vote in the second round claiming the process was fraudulent.

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His call for a boycott has drawn wide international condemnation, and raised fears for the legitimacy of an election billed a litmus test of the nation's fragile democracy and hard-won peace.

US President Barack Obama warned in a statement hours before the polls opened that Liberians should be able to vote free from fear and warned unnamed individuals not to "disrupt the political process."

"This historic vote is an opportunity for Liberians to strengthen the country's democracy, and to deepen its peace, prosperity and national unity," Obama said in a statement issued after the election-eve violence.

Several schools which had served as polling stations in the first round where closed, fearing a repeat of Monday's violence.

Shooting erupted on Monday as tensions soared between anti-riot police, UN peacekeepers and thousands of protesters gathering for an unauthorised march called by Tubman a day after the official end of campaigning.

"Some school buildings have denied us access to their premises. We are still negotiating with them to see if they will allow us," National Elections Commission chairwoman Elizabeth Nelson told the UN Mission in Liberia (UNMIL) radio.

"Because of the incident yesterday all the voting centres did not open on time."

Some 1.8 million voters have registered for the election. Despite his boycott, Tubman will still appear on the ballot paper.

Sirleaf, who made history when she became Africa's first elected female president in 2005 and jointly won the Nobel Peace Prize shortly before the first round, has accused her rival of violating the constitution.