By Alphonso Toweh
MONROVIA (Reuters) - Liberia's ruling party, whose candidate finished runner-up in the first round of this month's presidential election, said on Sunday it would back a legal challenge to the result, accusing President Ellen Johnson Sirleaf of interfering in the vote.
The extraordinary charge by Unity Party against Johnson Sirleaf, one of its own members, throws into question a second round run-off scheduled for Nov. 7 between its candidate Vice President Joseph Boakai and front-runner George Weah.
Unity Party said in a statement that the Oct. 10 poll, meant to usher in Liberia's first democratic transition of power since 1944, "were characterised by massive systematic irregularities and fraud".
The statement, read to reporters by Unity Party Chairman Wilmont Paye, said Johnson Sirleaf had acted inappropriately by meeting privately with elections magistrates before the vote.
Unity Party officials said they were supporting a legal challenge by Liberty Party of the third-place candidate Charles Brumskine, which has petitioned the elections commission for a re-run of the first round.
"It doesn't mean we will not take part in the (run-off)," Augustine Ngafuan, Unity Party's national campaign chairman, told Reuters. "We hope the court can rule before the run-off. If not, we will decide what next to do."
A spokesman for Johnson Sirleaf declined to comment immediately on the accusations against her.
International observers from the European Union, the Carter Center and the National Democratic Institute have said they saw no major problems with the vote.
Boakai has served as Nobel Peace Prize laureate Johnson Sirleaf's vice president since her inauguration in 2006.
But the relationship has soured of late. Johnson Sirleaf declined to endorse Boakai, who has distanced himself from the last administration and touted himself as a candidate for change.
Weah won the first round with 38.4 percent of the vote to Boakai's 28.8 percent and has momentum headed into the run-off. On Thursday he won the endorsement of former warlord Prince Johnson, who won 8 percent of the vote in the first round.
The elections commission said last week it would respond to complaints as quickly as possibly and said parties could challenge the commission's findings at the Supreme Court if they were not satisfied.
(Additional reporting by James Giahyue; writing by Aaron Ross; editing by Jason Neely)