Abdel Aziz Hakim, leader of a formerly Iran-based religious party that is one of the main planks of the Shiite United Iraqi Alliance, ruled out any possibility of re-runs as demanded by the Maram umbrella group contesting the conduct of the vote.
"The election results cannot be invalidated," said Mr Hakim, head of Supreme Council for the Islamic Revolution in Iraq. "Elections cannot be held anew."
Mr Hakim also rejected any role for the Arab League or United Nations in reviewing the December 15 elections, as called for by Maram, Arabic acronym for the Conference Rejecting Rigged Elections.
Iraqis must accept the results of a vote which was legally organised and supervised by an independent electoral commission, he said.
Mr Hakim was addressing a joint news conference with the head of the Kurdish regional government, Massud Barzani, and reiterated that the Shiites intended to embrace the Kurds in a renewed governing coalition.
Mr Barzani responded that the Kurds favoured a government with "a broad popular base", in line with earlier calls from Iraqi President Jalal Talabani, a fellow Kurd, for a government of national unity.
Poll protests
The news conference followed a demonstration in Baghdad joined by more than 5,000 supporters of Maram protesting the conduct of the election and demanding a re-run.
"No democracy without real elections", "Rigged polls", "Down with the electoral commission," read some of the banners carried by the demonstrators.
Maram spokesman Ali al-Tamimi said the rally was meant to "show the Iraqi people's rejection of ballot-rigging" in the election.
A similar demonstration was held in Saddam Hussein's hometown of Tikrit, north of Baghdad.
The electoral commission has acknowledged receiving some 1,500 complaints, but has said only a couple of dozens are serious enough to warrant annulment of some of the results.
Final results are not expected before next week.
Meanwhile a top defence ministry official, Major General Abdul Aziz
Mohammed Jassim, accused insurgents of spreading false information "to cast doubt on the fairness of the elections" and incite "disorder and riots".
In the Shiite holy city of Karbala, hundreds demonstrated in support of the election results and called for a new term for Shiite Prime Minister Ibrahim al-Jaafari.
"We voted for who we wanted to represent us, in total freedom and without any fraud and we demand that our vote be preserved and not be thrown away," said demonstrator Mohammed Jassim Hussein, who carried a poster of Shiite spiritual leader Grand Ayatollah Ali Sistani.
Mass grave
Workers laying pipes in the pilgrimage city uncovered the remains of women and children, believed to be victims of Saddam Hussein's ousted regime, in an unmarked mass grave, a local official said.
An initial 20 bodies were exhumed and taken to the city hospital for DNA testing, the official said.
The dead appeared to have been victims of Saddam's bloody suppression of a Shiite uprising that followed the 1991 Gulf war.
The US-installed provisional authority suggested in 2004 that about 259 mass graves containing about 300,000 people had been located since Saddam's ouster.
In violence on the ground, at least 11 Iraqis, including an army colonel were killed, while security sources boasted the capture of two commanders of an Al-Qaeda-linked militant group.
The sources named the pair detained south of the northern oil centre of Kirkuk as Arkan Mohammed Ali, local commander of Ansar al-Sunna and aide Khalaf Bayati.
Two US pilots also died when their Apache attack helicopter crashed in west Baghdad Monday evening, but the military ruled out hostile fire.
Poland confirmed it would maintain its contingent in the US-led coalition until the end of next year as Bulgaria announced the departure of the last of its troops.
"The government has asked President Lech Kaczynski to extend the mandate of Polish forces in Iraq from January 1, 2006 until December 31, 2006," Prime Minister Kazimierz Marcinkiewicz told a press conference in Warsaw.
Earlier Bulgarian Defence Minister Vesselin Bliznakov announced in Sofia that "the last 130 troops of the Bulgarian contingent are since last night safe in Kuwait."