Electoral officials and politicians said the decision may not alter the final outcome of the election, but a more significant ruling was expected on April 27, when the panel considers the fate of six to nine winning candidates.

Former Prime Minister Iyad Allawi, whose cross-sectarian Iraqiya alliance won a slim lead with strong support from the Sunni minority, said his coalition will fight the ruling while some of his allies said they might seek a new election.

"We have instructed lawyers to appeal against the panel's decision," Allawi said in Ankara. "We are very concerned about certain groups controlling the political process in Iraq."

Allawi and other Iraqiya leaders demanded U.N. intervention.

"We will not accept this election and its results if it continues like that. We will call for a new election ... under direct international observation and the U.N. will carry out this election," senior Iraqiya member Osama al-Nujaifi said.

Saad al-Rawi, one of nine commissioners at the Independent High Electoral Commission (IHEC), of which the review panel is a part, said one winning candidate was affected.

"I don't think this would affect the number of seats for the (Iraqiya) bloc," Rawi said. "Iraqiya got millions of votes, 5,000 or 10,000 votes (less) would not affect it."

"This decision (of the review panel) builds a wall between the political parties when they should be getting closer to forming a government quickly," said Khamis al-Badri, a professor of political science at Baghdad University.