Partial election results from six of Iraq's 18 provinces showed the cleric-endorsed Shiite ticket running strong for seats Thursday in the National Assembly.
Meantime, election officials said they have sent a team to the city of Mosul to look into allegations of irregularities in the surrounding Ninevah province during last week's balloting.
The United Iraqi Alliance, which is backed by the country's most influential Shiite cleric, Grand Ayatollah Ali al-Sistani, was leading in the six provinces, according to the partial results from the Baghdad, Dhi Qar, Muthanna, Qadisiyah, Najaf and Karbala provinces.
The vote count ranged from 25 percent in Baghdad province to 70 percent in the sparsely populated province of Muthanna.
In Baghdad province, the United Iraqi Alliance was leading 3-1 against its closest opponent, the list of candidates led by interim Prime Minister Ayad Allawi.
Allawi's list was running second in the other five provinces as well.
Those are predominantly Shiite areas, and the Alliance was expected to dominate there.
However, the figures were so small that it was impossible to say whether they represented the nationwide trend. It also was unclear where in Baghdad the partial results came from.
According to Iraq's election commission, 1.6 million votes have been counted so far from 10 percent of the country's polling stations.
The partial results for the two leading factions showed the Alliance winning more than 1.1 million votes in the six provinces. Allawi's list was second with more than 360,500 votes.
Iraq's Shiites, who make up about 60 percent of Iraq's estimated 26 million people, turned out in large numbers in Sunday's balloting, hoping to reverse decades of oppression under Iraq's Sunni Arab rulers. The Sunni minority lost its position of privilege and influence with the fall of Saddam Hussein.
The officials repeated that it would take seven to 10 days from the Sunday vote before certified results would be announced although that timeframe appeared to be slipping.
Investigation into voting complaints
Separately, officials said a team was sent to Mosul to investigate alleged polling irregularities.
Officials were vague about the nature of the complaints, which have included polling stations running short of ballots, confusion over the location of polling centers and ongoing military operations.
Some Sunni Arabs and others in the ethnically mixed city complained about having been denied the right to cast ballots around Mosul, Iraq's third largest city.
A team of three lawyers has been dispatched to Mosul to investigate alleged irregularities.
"We received some complaints and the legal department in our commission is studying these complaints thoroughly," said Safwat Rasheed, an election commission official.
Some polling stations never opened in Mosul, and ballot papers couldn't be delivered to some sites, Rasheed said.
He said he didn't know how many voters were affected.