Sunni Arab and secular parties in Iraq have threatened to boycott the new parliament, complaining that last week's elections were marred by fraud.
Sunni parties had previously praised the election
At a meeting in Baghdad on Wednesday, they formed a united front to contest the results that saw the main Shia-led coalition maintain its dominance.
Iraq's election commission says it has received complaints, but does not think the overall results will be affected.
The final results are expected to be announced at the beginning of January.
Partial results released this week said the Shia-led United Iraqi Alliance was ahead in Baghdad, Basra and eight other southern provinces, while the Kurdistan Alliance was leading in four northern provinces, including oil-rich Tamim.
In the four remaining provinces, where the population of Sunni Arabs is largest, the main Sunni coalition, the Iraqi Accord Front, came top, closely followed by Saleh al-Mutlak's Iraqi Front for National Dialogue.
Former Iraqi Prime Minister Iyad Allawi's secular Iraqi National List was shocked to find it may win barely half the 40 seats it has in the current parliament.
Representatives of the two Sunni Arab blocs and Mr Allawi's Iraqi National List met on Wednesday to discuss the results and agree on a strategy to contest the results.
IRAQ ELECTION FACTS
275-seat National Assembly will have four-year term
18 provinces are taken as separate constituencies
230 seats allocated according to population
45 seats distributed to parties whose ethnic, religious or political support is spread over more than one province
15 million eligible voter
One third of candidates in each party must be women
"We want a new election and we're going to ask the United Nations to help organise it," Thair al-Naqib, a spokesman for Mr Allawi, told the Guardian.
"I know it's not easy to rerun an election. But if they refuse, we will boycott the new parliament."
Mr Naqib said the parties wanted a new government to rule while a new election was prepared.
"If our demands are not met, we will take further steps and create a lot of protest," he added.
The parties accused the Iraqi police of supporting the ruling Shia coalition in Baghdad in particular.
Hamid Musa, leader of the Iraqi Communist Party, also accused some members of the electoral commission of being unwilling to issue judgements on complaints against the major parties.
The parties will meet again on Thursday.
'This is democracy'
Mazen al-Jumaili of the Supreme Council of the Islamic Revolution in Iraq, a member of the governing United Iraqi Alliance, told the BBC that some violations were to be expected.
"Tell me about another country that doesn't have such incidents here and there. This is democracy," he said.
"You are doing democracy in a country which hasn't been democratic for centuries. We think that it's a fair election and has been supervised by international observers and the United Nations."
The US was also confident the election had been free and fair, and said it was confident the Iraqi election commission would investigate any complaints systematically.
"Their track record of following up on these things has been pretty good in the January elections and the October referendum," State Department spokesman Sean McCormack said on Wednesday.