Liberia's Supreme Court has ordered preparations for Tuesday's presidential run-off vote be halted amid allegations of fraud from an eliminated candidate.

Ex-football star George Weah and Vice-President Joseph Boakai are due to go head-to-head in the 7 November vote.

But the Liberty Party's Charles Brumskine, who came third in the first round, has challenged the result.

Last month's election was the country's first independently run vote following the end of civil war in 2003.

But Mr Brumskine and the Liberty Party said it was "characterised by massive systematic irregularities and fraud", including polling stations opening late and therefore preventing people from voting.

The accusation of irregularities is backed by two other political parties - including Mr Boakai's Unity Party, which on Sunday alleged its own president interfered in the process.

In a statement, it said Ellen Johnson Sirleaf, Africa's first female elected president and a winner of the Nobel Peace Prize, had attempted to influence the outcome of the poll.

Ellen Johnson Sirleaf is accused of not supporting her deputy's presidential bid

Relations between Ms Johnson Sirleaf and her deputy are not warm, with some ruling party people saying her choice to succeed her is not the vice president, the BBC's Jonathan Paye-Layleh reports from the capital Monrovia.

This is despite the 79-year-old saying more than twice that she supports Mr Boakai, who won 28.8% of the vote compared to Mr Weah's 38.4% in the first round.

Mr Weah's Congress for Democratic Change (CDC) party responded to the accusations by noting it was "sad for a ruling party that has been in power for 12 years [to] be crying".

Meanwhile, international observers, including the European Union, had not raised major concerns about the first round of voting, although some irregularities were observed, AFP news agency reports.

The court has instructed the Liberty Party and the electoral commission to present their cases by Thursday.

However, election commission spokesman Henry Flomo told the BBC it had not yet been officially informed of the Supreme Court's order, made late on Tuesday.

But if there is an injunction, the commission will abide by it as the Supreme Court is the highest court and its decisions are final, Mr Flomo added.

Both the Supreme Court and electoral commission were guarded by riot police on Wednesday, Reuters news agency reported.