Iraq's U.S.-appointed Governing Council on Friday unanimously nominated Ayad Allawi, a Shiite Muslim politician and former exile whose party was supported by the CIA, to be the country's interim prime minister.

The council's selection of Allawi, a physician who left Iraq in 1971, was quickly endorsed by L. Paul Bremer, the U.S. civilian administrator of Iraq, and later by Lakhdar Brahimi, the U.N. representative who is leading efforts to form an interim Iraqi government, council members said. A senior Bush administration official in Baghdad who spoke on the condition of anonymity said Allawi would become Iraq's post-occupation prime minister, the most powerful position in the new government.

Allawi, 58, is regarded by some U.S. officials as a compromise candidate well suited to lead Iraq until national elections early next year. Although he is secular, he reportedly has the support of the country's top Shiite cleric, and he has served as the Governing Council's point man on security issues. He also has welcomed Sunni Muslims and ethnic Kurds into his political organization and promoted reconciliation with former members of Saddam Hussein's Baath Party, a group he supported more than 30 years ago.

But that tie, along with Allawi's links to the CIA and his three-decade absence from the country, could prove controversial among ordinary Iraqis, who remain deeply suspicious of politicians who lived abroad and were backed by Western governments. Almost 14 months after the fall of Hussein's government, public opinion polls indicate that Allawi has not emerged as a widely popular national leader.

There were differing accounts of how Allawi came to be selected by the council and subsequently endorsed by Bremer and Brahimi. The senior administration official said Allawi was recommended by Brahimi after the U.N. envoy conducted numerous meetings with Iraqi political, tribal and religious leaders.

But a U.N. official familiar with the process said Allawi was not Brahimi's top choice. Instead, Allawi lobbied other council members to support his candidacy over the past few weeks, eventually generating enough critical mass to compel the backing of Brahimi and the Bush administration, the official said.

Allawi, a tall man with a round face, made his move after Shiite politicians on the council rejected Brahimi's top choice, nuclear scientist Hussain Shahristani, a Shiite, the official said. Brahimi had wanted a prime minister who, like Shahristani, was not a council member or affiliated with a political party, reasoning that such a person would be best suited to prepare the country for elections. But council members insisted that the prime minister be a leader of a large Shiite political party, council sources said, adding that some members even hinted that they would withhold support for the interim government if Brahimi did not pick a Shiite politician.

When Shahristani withdrew from consideration, the United Nations and the United States were left with three viable choices: Allawi, Adel Abdel-Mehdi of the Supreme Council for the Islamic Revolution in Iraq and Ibrahim Jafari of the Dawa party. All three are members of the Governing Council.

Because the Supreme Council and Dawa are religious parties with almost no non-Shiite members, the official said, Abdel-Mehdi and Jafari were less attractive to Brahimi, Bremer and presidential envoy Robert D. Blackwill, the trio charged with forming the interim government. At the same time, Allawi appeared to be gaining the most support on the council because of his politicking.

"Mr. Brahimi did not pick this candidate," an official involved in the process said. "He simply endorsed a consensus of the Governing Council."

"The name did not come" from the Governing Council, the official said. "It was terrific they endorsed the name, but the name came out of this Brahimi process."

The administration official said Allawi emerged as the leading candidate in the extensive consultations that Brahimi, Bremer and Blackwill had with various groups of Iraqis. "It was just pure democratic politics," the official said. "One candidate got a lot of momentum."

The official said other candidates on Brahimi's list were not "acquiring much support" among Iraqis being consulted. But the U.N. official said most of the consultations involved Governing Council members who had an incentive to choose one of their own.

The Governing Council's acting president, Ghazi Yawar, eventually decided to schedule a special meeting on Friday afternoon to endorse Allawi's candidacy. At the meeting, the normally fractious council unanimously backed Allawi within minutes.

"Ghazi nominated him and said, 'We have this name and I want to vote on it,' " said Rajaa Habib Khuzai, a Shiite member of the council. "Nobody said anything. We just raised our hands."

Three of the council's 23 members were absent for the vote, including Ahmed Chalabi, the leader of the Iraqi National Congress. Allawi's Iraqi National Accord is a longtime rival of the Iraqi National Congress, an exile group once favored by the Pentagon. The Iraqi National Accord enjoyed support from both the CIA and the State Department in efforts through the 1990s to overthrow Hussein.

U.N. spokesman Fred Eckhard said the United Nations had not expected the Governing Council to make the announcement, "but the Iraqis seem to agree on this candidate," he said. "And if they do, Mr. Brahimi is ready to work with this candidate. If this is the Iraqi way, he's ready to go with it and work with it and try to complete the process by the end of the month."

Khuzai and other council members praised Allawi, noting his role as the chairman of the council's security committee. "He's the best man for this very critical period that we are in," said Khuzai, who attended medical school in Baghdad with Allawi in the 1960s.

Ahmed Shyaa Barak, another Shiite member, acknowledged that Allawi lacked wide public support, but he said other skills made him the right person for the job. "Dr. Allawi has good connections with the British and American governments, and that will be important for us," Barak said.

A half-hour after the council's vote, Bremer entered the council chambers and congratulated Allawi. An hour later, Brahimi came in and also congratulated him.

In a statement issued by the United Nations, a spokesman for Brahimi said the envoy "is perfectly comfortable with how the process is proceeding thus far."

Allawi, who made no public comments, is a member of a prominent Shiite merchant family. He joined the Baath Party as a young man and organized party meetings at his medical school. He left Baghdad for advanced medical studies in London in 1971, eventually becoming a neurologist.

He resigned from the party in 1975 while in London, but Hussein tried to lure him back with threats and bribes. When he refused and subsequently struck up a relationship with the British intelligence service, he was reportedly placed on a liquidation list by Hussein.

Iraqi secret police were sent to assassinate Allawi in London in 1978, bursting into his bedroom and hacking him with an ax. He suffered serious injuries and spent nearly a year in a hospital. He continues to walk with a limp because of injuries to his leg suffered in the attack.

In 1979, he began organizing an anti-Hussein network, which became the Iraqi National Accord in 1990. As leader of the INA, he was embraced by Britain and the United States. In 1996, he worked with the CIA to plot a coup that was to involve Iraqi army generals toppling Hussein. But the Iraqi leader penetrated the plot and arrested and executed many of its operatives.

Allawi returned to Baghdad shortly after Hussein's government fell in April 2003, running his party from an abandoned Baath Party office. Many members of his party are former military officers, and he has advocated a greater role for former soldiers in the country's new security services.

A U.N. official said Allawi would work with Bremer and Brahimi to select 25 cabinet members over the next few days. The U.N. envoy and U.S. officials also must select a president and two vice presidents.