The selection of Iraq's interim national assembly, envisioned as an introductory exercise in legislative democracy, dissolved into bitter feuding Wednesday as a slate of independent candidates withdrew from the contest, handing a controversial victory to a bloc dominated by large political parties.

Some political independents stormed the stage and later angrily walked out of the meeting hall where a national conference of more than 1,100 Iraqi leaders had convened for four days to elect an assembly. Independents said their quest for representation was sabotaged by major political parties expected to support interim Prime Minister Ayad Allawi.

After the withdrawal of the independents, conference organizers approved a slate of candidates from the major parties without a secret vote. Four cardboard ballot boxes placed on the stage remained unused, and many delegates abandoned the meeting hall to collect their $100 per diem payments instead of participating in a show of hands.

"There was no transparency," growled Ismael Zayer, a newspaper publisher who had helped organize the slate of independent candidates that withdrew. "The parties didn't give us a chance. They played this game in the most unfair way."

The interim assembly will have authority to veto decisions by Allawi's government until it is replaced following national elections scheduled for January. For the first three days of the conference to choose the body, the process seemed to live up to its promise as a model of accommodation among Iraq's diverse constituencies of Shiite and Sunni Muslims, Arabs and Kurds, sheiks and professionals.

Under rules set by conference organizers, delegates were not able to run for election to the 100-member assembly as individuals. Rather, they had to form 81-member slates that would be voted on by delegates. The 81 would be augmented by 19 Iraqis who had served on the former U.S.-appointed Governing Council.

Each slate was required to meet quotas designed to ensure adequate representation of Iraq's provinces, tribes, civil society groups and ethnic minorities. At least 25 percent of members had to be women.

Independents and leaders of small parties said the process was inequitable because the country's five largest political parties banded together behind closed doors to form one slate. With the five parties working together, the independents said, there was no way others could compete.

Delegate Mansour Kenaan, who walked out with a dozen others from the southern port city of Basra, accused the political parties of "a conspiracy behind closed doors."

"We have been shut out!" screamed Aziz Yasiri, the leader of a small Shiite party.

The five parties whose members dominate the winning slate include the Iraqi National Accord, which is led by Allawi. Two are Shiite religious parties: the Supreme Council for the Islamic Revolution in Iraq and the Dawa party. The two largest ethnic Kurdish parties, the Kurdish Democratic Party and the Patriotic Union of Kurdistan, round out the slate. The five parties had led the opposition to the government of Saddam Hussein from exile before his ouster by U.S.-led forces 16 months ago.

Many members of the winning slate, called the Iraqi National Union, are well known among their constituencies but lack nationwide recognition. Composition of the new assembly, including the breakdown between Shiites and Sunnis, was not released by conference organizers.

U.N. officials advising Iraq on the selection of the assembly had recommended a different process that would have provided more opportunities for independents and smaller parties, but it was rejected by Iraqi political leaders who organized the conference, according to sources involved in the process.

The conference started Sunday after a two-week delay to attract more participants. The gathering was supposed to be limited to 1,000 members, but political advisers from the United Nations asked organizers to invite 300 additional people, many from religious and ethnic groups that were deemed underrepresented.

Fouad Masoum, the chairman of the conference, defended the use of slates and blamed the independents and small parties for not building a stronger political coalition. "It was democratic, but the problem was the opposition wasn't united," he said.

Iraqi political leaders contend that having a few large parties dominating the assembly will make it easier to forge coalitions and build consensus. "An assembly full of independents would get nothing accomplished," said a senior Shiite politician.

Zayer contended that the large parties conspired to send low-ranking members to join the list of independent candidates. Shortly before the vote, several members of the independent list dropped out, forcing Zayer and others to scramble to find replacements. When they could not keep their group together, they decided to withdraw.

"We didn't have enough time and we didn't have the means," he said at the conference. "We are making this sacrifice for all the people of Iraq. We would have liked to be in a stronger position and a dignified opposition holding its head up high -- and we will be that in the future."

Even before the withdrawal, the selection process was roiled by disputes. Two Chaldo-Assyrian Christians squabbled over who should represent their small community. A man from a small Muslim sect demanded that he be given a seat. And several delegates from Basra began screaming after they learned that the Iraqi National Union slate had only one member from their city.

"Where are the martyrs?" shouted Esraa Saad, a middle-aged woman whose voice pierced the hall.

"Basra has been marginalized," added another resident. "Its children have been killed. Basra wants more representation. It is the source of oil."

As disorder ensued, the chairman of the session, Walid Shaltagh, sought to restore order. "Ladies and gentlemen, you are the representatives of the Iraqi people," he implored. "What you are asking for is right, but not in this unseemly way . . . not in this chaotic way."

When the Basra delegation learned that it was not getting any more seats, about a dozen members stormed out.

Delegates protest during conference to choose Iraq's interim assembly. A slate of independent candidates withdrew from the process, calling it unfair.