The impasse, two months after the country's historic national elections, is rooted in disagreements about the posts that should be granted to Sunni Arabs, an attempt to incorporate in the new government members of the minority group that dominated under ousted dictator Saddam Hussein.
The Sunni Arab minority — believed to be the backbone of the insurgency — was given until Sunday to come up with a candidate to serve as speaker.
"We saw that things were confused ... so we gave (the Sunnis) a last chance," said Hussein al-Sadr, a Shiite cleric and member of interim Prime Minister Ayad Allawi's coalition. "We expect the Sunni Arab brothers to nominate their candidate. Otherwise, we will vote on a candidate on Sunday."
In other developments
The Shiite-led United Iraqi Alliance party, along with the Kurdish coalition, want a Sunni Arab to take the parliament speaker post as way to bring more Sunnis into the new government. Many Sunnis boycotted the Jan. 30 elections or simply stayed home because they feared attacks at the polls.
Officials lobbied a prominent Sunni Arab leader, interim President Ghazi al-Yawer, to take the job. But he held out for one of two vice presidential spots. The Sunni-nominated candidate, Adnan al-Janabi, was vetoed by the Shiites and Kurds due to his brother's ties to Saddam's former regime.
Some politicians speculated that the delay could force them to request a six-month extension to the Aug. 15 deadline for drafting the country's permanent constitution. But most were opposed to the idea.
The assembly still needs to name an Iraqi president and two deputies, who will in turn nominate a prime minister. The presidency is expected to go to Kurdish leader Jalal Talabani and the premiership to Shiite politician Ibrahim al-Jaafari.
Negotiations over the top posts in the different ministries also continue, with both the Kurds and Shiites vying for the Oil Ministry position. Some Sunnis hope to get the Interior Ministry post, but the Alliance wants them to have the Defense Ministry position instead.
Together, the Alliance and the Kurdish coalition have 215 seats in the 275-seat National Assembly — enough to push through their proposals. But they have been reluctant to alienate the Sunni Arabs and other minority groups, saying they want an inclusive government.