WASHINGTON – Frustrated and worried, 30 supporters of Ahmad Chalabi met yesterday at the home of their candidate for prime minister and formed a caucus that may vote against the United Iraqi Alliance which just nominated Ibrahim Jafari for prime minister, on key issues such as the drafting of the constitution.

The development came after the Islamist parties blocked a vote Tuesday inside the largely Shiite alliance for the nomination of a prime minister, prompting Mr. Chalabi to withdraw his bid. While Mr. Chalabi said at the time that he dropped out of the race for the sake of the voting bloc’s unity, the following day he hosted a meeting in his Mansour neighborhood home in Baghdad to discuss a new voting bloc dedicated to a secular government in Iraq.

One of the organizers of the meeting, UIA delegate Mudhar Shawkat, told The New York Sun yesterday that he expects to pry at least 50 total legislators from the 140-person UIA slate for his caucus. He said yesterday that he expected the new group to nominate its own secretariat and meet weekly inside the new 275-person transitional Assembly to discuss legislative strategy distinct from the dictates of the UIA slate. Mr. Chalabi could not be reached for comment.

“This coalition is going to vote as a bloc for a constitution according to its belief that it be secular and not what Sciri or Dawa says inside the alliance,” Mr. Shawkat said. Sciri is the acronym for the Supreme Council for the Islamic Revolution in Iraq, the political party that threw its weight behind Mr. Jafari, the leader of a faction of Dawa, which means Islamic Call.

Both parties were headquartered in Iran during most of Saddam Hussein’s reign. The militias of the two parties were trained by Iran’s Revolutionary Guard. The meeting at Mr. Chalabi’s home came on the same day that Iyad Allawi, interim prime minister, announced his intention to form his own political alliance to counter the Jafari nomination from the UIA.

Under the complex rules of Iraq’s transitional administrative law, the transitional Assembly will elect a president and two vice presidents. This presidential council will then choose the prime minister. If they cannot reach a consensus, then the Assembly must elect the prime minister by a two-thirds majority.

“There are other lists and other brothers in smaller lists which won the elections,” Mr. Allawi said at a news conference in Baghdad, according to the Associated Press. “And we are working with some of those lists to form a national Iraqi democratic coalition which believes in Iraq and its principles.”

Mr. Shawkat said that he was particularly angry that leaders of Dawa and Sciri blocked a secret ballot vote for prime minister at the meeting on Tuesday. ” I do not object necessarily to Jafari if he was elected in a proper way. But he was not elected in a proper way,” Mr. Shawkat said. “We went to cast a ballot at that meeting, but there were no preparations for a ballot. All I saw was Ayatollah al-Hakim [the leader of Sciri] lecturing people on why the man of the hour should be Jafari and calling for unity.”

Mr. Shawkat said that individuals shouted down other nonaffiliated legislators in the meeting, shouting “God is Great” and other religious slogans.

In attendance at the meeting yesterday was Abdul Karim Al Muhammadawi, known as the “prince of the marshes” for his leadership of the 1991 Shiite resistance to Saddam. Also in attendance was a former member of the Iraqi Governing Council, Salama al-Khufaji, who is one of the highest-ranking women on the UIA list, as well as the highest-ranking Sunni Arab on the UIA list, a sheik who hails from outside of Mosul, Fawaz al-Jarba.

One of the concerns for many Iraqi legislators outside the UIA alliance is the connection Mr. Jafari has to the Islamic Republic of Iran.

The Sun reported yesterday that the Iranian ambassador in Baghdad told Mr. Chalabi on Monday that Mr. Jafari was Tehran’s choice for premier.

Mr. Jafari’s Dawa party in the 1980s was considered a terrorist organization by the State Department for its role in the December 1983 bombing of the American and French embassies in Kuwait. While Dawa has gone through numerous changes since then, splitting into different branches, Mr. Jafari was a member of the organization at the time.

David Mack, a former deputy assistant secretary of state for Near East affairs, told the Sun yesterday that Mr. Jafari met with American officials after the first Gulf War, nonetheless. “Based on what I know of the record, there has never been any evidence that Jafari was involved in acts of terrorism. Obviously one or another faction of Dawa have been involved in acts of terror, but Jafari himself, was not.”