Iran's top legislative body said on Friday it had found no major violations in the June 12 presidential election and called it the "healthiest" vote since the 1979 Islamic Revolution, Reuters reported.
"The Guardian council has almost finished reviewing defeated candidates' election complaints ... the reviews showed that the election was the healthiest since the revolution ... There were no major violations in the election," said Abbasali Kadkhodai, spokesman of the council.
The council had already rejected a call by moderate former Prime Minister Mirhossein Mousavi, declared second in the election behind incumbent President Mahmoud Ahmadinejad, for the vote to be annulled.
Its statement is the latest step in a behind-the-scenes struggle since the election, which has split the clerical establishment into two camps.
The leadership has quelled mass protests over the election and hardline preacher Ayatollah Ahmad Khatami is expected to reinforce the message that the election was free and fair when he leads Friday prayers.
Mousavi's supporters plan to release thousands of balloons on Friday with the message: "Neda you will always remain in our hearts", in memory of the young woman killed last week who has become an icon of the protests.
The last mass protests were on Saturday and a combination of warnings, arrests and the threat of police action have driven large demonstrations off Tehran's street with small gatherings dispersed with tear gas and baton charges.
The worst unrest since the 1979 revolution led to the killing of about 20 people, prompting President Barrack Obama to say he was "appalled and outraged" by the security crackdown in the world's fifth largest oil exporter.
Group of Eight powers meeting in Trieste plan in a statement to deplore post-election violence, to urge Tehran to settle the crisis through peaceful, democratic means and to respect basic rights including freedom of expression, a diplomat said.
The condemnation by Obama, who had been trying to improve ties with Iran before the election, prompted Ahmadinejad to accuse him of behaving like his predecessor and say there was not much point in talking to Washington unless Obama apologised.
Mousavi said he was determined to keep challenging the election results despite pressure to stop.
"A major rigging has happened," his website reported him as saying. "I am prepared to prove that those behind the rigging are responsible for the bloodshed."
He called on his supporters to continue "legal" protests and said restrictions on the opposition could lead to more violence.