Sunni Arab and secular parties in Iraq have united to reject the results of last week's parliamentary elections, saying there was widespread fraud.
Sunni parties had previously praised the election
Representatives from 35 parties issued a statement threatening to boycott the new parliament if their complaints were not properly investigated.
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 by the Independent Electoral Commission of Iraq (IECI) this week suggested that the Shia-led United Iraqi Alliance would maintain its dominance in the new Council of Representatives.
The UIA was ahead in Baghdad, Basra and eight other southern provinces, while its current coalition partner, the Kurdistan Alliance, was leading in four northern provinces.
The only significant changes have come in the four provinces where the population of Sunni Arabs is largest.
There, the main Sunni Arab coalition, the Iraqi Accord Front, came top.
The Iraqi Accord Front was joined at the meeting in Baghdad's Green Zone by the other main Sunni bloc, Saleh al-Mutlak's Iraqi Front for National Dialogue, and former Iraqi Prime Minister Iyad Allawi's secular Iraqi National List.
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 totally reject the results of these rigged elections and call for the cancellation of the early results," a joint statement issued by the parties said.
"We hold the IECI responsible for all the violations which took place during the elections and demand that it be dissolved and a suitable alternative to be found," it added.
"If this is not achieved, then we will have no choice but to refuse the results and boycott the new parliament."
Ibrahim al-Janabi, a spokesman for the Iraqi National List, said his party had lost confidence in the political process.
"These elections are fraudulent, and the next parliament is illegitimate," he said.
Mazen al-Jumaili of the Supreme Council of the Islamic Revolution in Iraq, a member of the United Iraqi Alliance, told the BBC on Wednesday that some violations were to be expected, but that they were not significant.
The US was also confident the election had been free and fair, and said it believed the Iraqi election commission would investigate any complaints systematically.