Liberia's incumbent President Ellen Johnson Sirleaf has increased her lead in the country's presidential election, but is still short of the 50 percent majority needed for an outright victory.

Election officials said Friday that Ms. Sirleaf now leads with more than 45 percent of the vote, up from about 44 percent the day before. Her closest rival Winston Tubman has garnered less than 30 percent so far. With about a half of the ballots counted, former rebel leader Senator Prince Johnson remains in third place, with about 11 percent of the vote.

Election observers from the Economic Community of West African States say the vote was largely free and fair and that ballot counting is proceeding smoothly. The U.S.-based Carter Center agreed, noting only minor irregularities.

The electoral commission has until October 26 to announce the final results.

As a run-off election seems more and more likely, Johnson's supporters could give their votes to either candidate to help them win. If needed, the second-round vote will take place November 8.

Johnson said he is not in rush to make a decision on which of the two front-runners to support. He said after consulting with his supporters, he will stand behind the candidate that offers his party a more influential role in the government.

The vote held Tuesday was the country's second national election since the end of a 14-year civil war in 2003.