Politicians on Iraq's U.S.-appointed Governing Council are pushing for significant changes in the interim government being crafted by a U.N. envoy, posing a new complication to the Bush administration's plan to relinquish civilian administrative powers here in 50 days.

With the Iraqi Governing Council set to dissolve on June 30, members said they wanted to form a new national council in order to retain influence in the interim government. The members want a new council to share power with the government outlined by Lakhdar Brahimi, the U.N. special envoy for Iraq. Brahimi's blueprint envisions a caretaker executive branch consisting of a president, a prime minister and a 25-member cabinet of specialists, according to U.S. and U.N. officials.

Senior U.S. officials responsible for Iraq policy oppose the Governing Council's idea. But council members said they would not abandon the proposal because they said the country's interim constitution gives them the authority to form the transitional government that will replace them. They added that proposals advanced by Brahimi, a veteran diplomat whose role has the endorsement of the Bush administration, are not binding.

"We shall listen to the ideas of Mr. Brahimi, but his ideas are not compulsory for us," said Izzedine Salim, the current holder of the council's rotating presidency. "The Governing Council is the one responsible for forming the government."

In contrast with Brahimi's proposed executive branch, which emphasizes technical expertise over political connections, Governing Council members are calling for another body in the interim government that would be composed of representatives of various political groups. Such a body would give the new government credibility, they insist, and it would provide an essential check on the executive.

"The new government needs political weight," said Adel Abdel-Mehdi, a senior leader of the Supreme Council for the Islamic Revolution in Iraq, a large Shiite Muslim political party. "The major, important political parties and currents should be there."

Brahimi has said he supports the idea of convening a large national conference in July to select an advisory body that would have limited powers. But Brahimi opposes forming such an entity before June 30 or granting it lawmaking powers, as some in the Governing Council are seeking, a U.N. official involved in the transition said. Brahimi has proposed an interim government of technical experts whose powers would largely be limited to the day-to-day operations of the country and preparing for national elections early next year, the U.N. official said.

"It should be a caretaker government," the official said.

Senior U.S. officials said Wednesday they supported Brahimi's proposal. The officials also said it would be impossible to hold a national conference before the planned June handover.

"That won't happen. It can't be done," a senior official with the U.S. occupation authority said. "It's simply not possible to have a conference in the time frame before the 30th of June."

Governing Council members are still debating the contours of a new entity, but they have said they want a body that would enjoy wide authority, including control over the budget and the right to appoint new cabinet members. "It will be a sort-of safety valve," Abdel-Mehdi said. "Since we will not have an elected government, it will assure people that we have controlled results and we are not going for a dangerous adventure."

The difference of opinion about the formation of a new council threatens to cause a confrontation between the occupation authority and many of its closest political allies in Iraq at a time when both sides deem cooperation crucial to the success of the handover of power. But so far, neither side appears to be budging.

There is little time remaining to resolve the matter. U.S. officials have said they want members of the interim government to be named by June 1, to give them a month to prepare for their new jobs.

It is not yet clear who will determine membership in the new government. Brahimi has said he will not decide and instead will consult with the occupation authority and the Governing Council. U.S. and U.N. officials said it was likely that Brahimi would weigh names in collaboration with members of the Governing Council and two senior representatives of the U.S. government: L. Paul Bremer, the civil administrator of Iraq, and Robert D. Blackwill, a senior official with the National Security Council who is in Iraq to work on the political transition. Officials close to the process said the choice of president and prime minister also will involve consultations with the White House, the State Department and the Pentagon.

Brahimi, Bremer and Blackwill have spent the past week meeting with various groups of Iraqis, from tribal sheiks to provincial leaders, in an attempt to identify promising candidates. Members of the Governing Council have been holding similar meetings.

Senior U.S. officials involved in the process said they had not reached any conclusions on who would be nominated. Brahimi also has not made any decisions, his spokesman said.

"It's a process that's evolving minute by minute, hour by hour," said the spokesman, Ahmed Fawzi. "We have more questions than answers at this stage."

U.S. and U.N. officials said they wanted to ensure that the new leaders focused on holding fair elections early next year and not holding onto power. As a result, they are trying to create a balance between politicians and technocrats who would not try to hijack the fragile new political process.

Ceremonial posts, including the presidency and two vice presidencies, likely would be given to established politicians, U.S. officials said. But the prime minister and cabinet that would run the government would be dominated by technocrats, the officials said.

"It'll be a mixture" of politicians and technocrats, a senior Bush administration official said. The senior occupation authority official noted that recent public opinion polls have shown that political parties do not enjoy wide support in Iraq, and therefore party leaders should not dominate the new government.

Senior U.S. officials maintain that many Governing Council members share the views of Brahimi and the occupation authority in opposing the formation of a new council. A senior U.N. official said Brahimi would not be swayed by holdouts on the Governing Council.

"You don't need all the members to say 'aye,' " the U.N. official said. "If there are a few naysayers, you can still pull it off."

Although the effort to form a new national council has been endorsed by a variety of current Governing Council members, including top Kurdish politicians, the leaders of the initiative are Shiites, according to Governing Council members and their aides. Shiite leaders have been suspicious of Brahimi, a Sunni Muslim from Algeria, and have openly questioned whether he would name a disproportionate number of Sunnis to cabinet posts.

While Sunnis have ruled Iraq for centuries, Shiites are now about 60 percent of the population. Shiite leaders have insisted that Shiites receive a majority of positions in the new government, including the prime ministership.

"Without a majority of Shia, Shia will not support this institution," Abdel-Mehdi said.

Shiite members, including Abdel-Mehdi and Ahmed Chalabi of the Iraqi National Congress, have been trying to convince the country's most powerful Shiite religious leader, Grand Ayatollah Ali Sistani, to support the creation of a new council. To date, however, Sistani has not issued any public statements on the subject. In earlier statements, Sistani has said an interim government should not have legislative powers. "Sistani is interested in an election and seeing that elections are held as soon and openly and conclusively as possible," a senior State Department official said. "So he wants to make sure the interim government doesn't prejudice the outcome of that election. Other than that, he's willing to let Brahimi do his work."

Staff writer Robin Wright in Washington contributed to this report.

An Iraqi schoolgirl runs past a barricade of burning tires in the Sadr City district of Baghdad, where U.S. forces clashed with militiamen loyal to radical cleric Moqtada Sadr. U.S. forces also pushed into the centers of the besieged holy cities of Najaf and Karbala. Story, Page A10.