WASHINGTON – The majority Shiite voting bloc in Iraq’s transitional assembly has nominated Iraq’s interim vice president, Ibrahim Jafari, as its choice for prime minister of the new government.

The choice was announced yesterday in Baghdad by the United Iraqi Alliance after the leader of the Iraqi National Congress, Ahmad Chalabi, withdrew from consideration for the post. After a week of intense negotiations, the alliance opted not to hold a vote among the caucus of 140 legislators.

Mr. Jafari’s nomination represents a victory for Iran, the country that provided Mr. Jafari sanctuary between 1980 and 2000. Mr. Chalabi’s announcement of his withdrawal followed a meeting on Monday with the Iranian ambassador. Mr. Chalabi’s spokesman, Entifadh Qanbar, described the meeting as “friendly.” Other sources close to Mr. Chalabi’s campaign said that during the meeting, the Iranians made it clear they preferred Mr. Jafari for the top post.

Mr. Chalabi has recently distanced himself from Iran. In December he gave a press conference in which he said the Iraqi government would not emulate the Iranian style of political system that grants clerics unaccountable political authority. Mr. Jafari has also said that Iraq will not emulate Iran’s system, though his aides have recently hinted that new laws should be vetted for their adherence to the Koran.

“Ahmad Chalabi had to withdraw his nomination for the prime minister to save the alliance’s unity, in spite of the fact that he had the majority of votes,” Mr. Qanbar said. Mr. Chalabi on Sunday told ABC’s “This Week” that he had a majority of votes within the UIA if it came to a secret ballot.

One UIA representative, who requested anonymity, said Mr. Jafari’s party, Dawa, and the Supreme Council for the Islamic Revolution in Iraq threatened to leave the coalition if a vote was taken. SCIRI in particular dominated local and provincial elections in southern Iraq.

At one point, according to this source, the leaders of the two parties, along with Mr. Chalabi and others, went into an adjoining room at the home of SCIRI leader Ayatollah Abdul Aziz al-Hakim, where the cleric leading the party announced his support for Mr. Jafari and again asked Mr. Chalabi to withdraw. This time Mr. Chalabi did. The Associated Press yesterday quoted Mr. Chalabi as saying he did so “for the unity of the alliance.”

Because the UIA controls 140 seats in the 275-person assembly, its choice for prime minister is expected to be chosen next month by a presidential council that body will elect. That council will be comprised of a president and two vice presidents. If the presidential council cannot agree, then the entire assembly must choose a prime minister by a two-thirds majority.

But Mr. Jafari’s nomination is by no means a lock. The Kurdish bloc that controls 77 seats in the new assembly will issue a set of written questions to Mr. Jafari on his views on federalism in the new state, on the role of the mosque, and most importantly on whether he will condone the continued resettlement of Kurdish families driven from oil-rich Kirkuk under Saddam Hussein.

“The Kurdish bloc will insure there will be a clear separation between church and state,” a Washington representative for the Patriotic Union of Kurdistan, Qubad Talabani, told The New York Sun yesterday. Mr. Talabani’s father, Jalal, is the frontrunner candidate for president.

“We will seek assurances on key principles such as democracy, the fact Islam is only one source and not the only source of law, and that article 58 of the Transitional Administrative Law, along with all other elements of it, will be adhered to,” Mr. Talabani said. “Kirkuk is a critical issue for any Kurdish leader. Steps must be taken to rectify the injustices committed by previous Iraqi regimes. Kurds must be given the right to return to their properties, and it should be left to the people of Kirkuk to determine who administers Kirkuk. This can only be done once Saddam’s ethnic cleansing policies have been reversed.”

Mr. Jafari has recently said that he is supportive in general of the principle of federalism, but has not yet specified his position on the administration or resettlement of Kirkuk. Mr. Jafari has also said that he supported the position in the transitional administrative law that made Islam only one, but not the only, source of law for the new constitution.

Nonetheless, Mr. Jafari’s party, Dawa, has consistently been one of the strongest advocates for a Sharia state in the new Iraq. In a Christian Science Monitor interview published on February 7, he said, “We also shouldn’t have anything that conflicts with Islam. Islam is the religion of the majority, so it should be the official religion of the state.”

A former American intelligence official yesterday confirmed a report in Newsweek that the CIA is concerned Iran may be able to infiltrate a new intelligence service if militias affiliated with the Dawa and SCIRI parties assume high posts in the military and security services. SCIRI’s militia, known as the Badr Brigade, is widely believed by American intelligence to have been trained by Iran’s revolutionary guard.