Over the coming days, Syria's anti-regime camp will wrangle over reorganizing its ranks, as the United States pushes a proposal to create a new leadership body with fewer Syrian exiles and more military commanders fighting on the ground to bring down President Bashar Assad.

But there are serious doubts whether the divided and ideologically diverse factions can come together into a structure the U.S. and its allies can work with.

Hundreds of Syrian opposition figures are taking part in a five-day conference starting Sunday in the Qatari capital Doha, seen as the most serious push yet to forge a united front to help end the 19-month conflict that has killed over 36,000 people and left much of the country in ruins.

For the United States, it represents an opportunity to overhaul Syria's fragmented opposition leadership, which is widely seen as petty, ineffective and cut off from the events on the ground. Washington hopes a more cohesive and representative body can provide a reliable partner, buffer against interference by extremists and help bring Syria's allies Russia and China on board with change.

The key issue is whether the main political opposition group, the Syrian National Council, which consists largely of academics and Syrian exiles, will accept a U.S.-backed proposal to set up a new 50-member leadership team with more representatives from inside Syria.

Under the new plan, called the Syrian National Initiative, the new leadership would include representatives of the rebels' Free Syrian army, political groups and local councils in Syria. The SNC would also be included but its influence would be diluted significantly.

Burhan Ghalioun, a senior SNC member, said Saturday that the group is willing to consider the idea, but hasn't decided yet. Potential members of the new leadership will discuss the initiative on Thursday. "We have agreed to attend the (Thursday) meeting, but there is no agreement to adopt the initiative as it is," Ghalioun told The Associated Press

U.S. officials have long complained that the opposition disarray has held back more robust foreign involvement behind the opposition in its fight to topple Assad. The SNC has been plagued from the start by infighting, splits and frustrations over its failure to broaden its membership. An opposition meeting in Cairo earlier this year descended into chaos, shouting matches and walkouts.

"We are hopeful that if this leadership structure can emerge in a new and enhanced way, it will be an organization that the international community can work with to better direct assistance, humanitarian assistance, non-lethal assistance, and other kinds of assistance," State Department spokeswoman Victoria Nuland said Friday.

She said the U.S. also hopes this new body will encourage more defections and give the Russians and Chinese "an address" where they can seek answers to questions about a post-Assad future.

But the SNC is not the only problem. Profound difficulties are also raised by Washington's desire to incorporate elements from the ground — "those who are on the front lines fighting and dying today to obtain their freedom," as U.S. Secretary of State Hillary Rodham Clinton has put it.

Rebel fighters are still split into multiple, self-created brigades of military defectors and Syrian civilians who took up arms, some led by prominent local figures little known outside Syria. Most nominally belong to the umbrella Free Syrian Army, but their ties to it are often just lip-service. Rebels have set up civilian council to run affairs in towns and neighborhoods under their control, but finding a way to represent them in the opposition leadership could also be tough. Over every level there are ideological differences, including between Islamists and secularists.

Anthony Skinner, an analyst at Maplecroft, a British risk analysis company, is doubtful the U.S. initiative at Doha will succeed.

"That the SNC has been ineffective does not solely derive from the fact that many of its members have long been exiled and have been disconnected from the population at large. This is one of many factors," he said. Serious doubts remain about whether the disparate opposition groups can work effectively under one umbrella, he said.

Already, the SNC is bristling, after Clinton said Wednesday that the Obama administration was suggesting names and organizations that should feature prominently in any new leadership to emerge from the conference.

"Only the people of Syria can decide who represents them and who doesn't. No one else has a say in that," said Abdelbaset Sieda, the SNC's outgoing president. He spoke in Istanbul on Saturday at a function aimed at raising funds for orphaned Syrian children.

Nuland said Friday that the United States is not "dictating" for the opposition.

"This is a matter of the U.S. and other friends of Syria, supporting the voices from inside Syria who are saying that the SNC has not, over the past year, used this time to really broaden itself," she said.

In a sign of the importance Washington is hanging on the Doha meeting, Nuland said the U.S. delegation has been upgraded and will now be led by Assistant Secretary of State for Near Eastern Affairs Elizabeth Jones.

The SNC itself called the Doha conference, and for the first four days it will hold talks on bringing other activists and representatives of Syria's various religious and ethnic groups under its own aegis.

One the last day, participants would discuss the Syrian National Initiative proposal.

The U.S.-backed initiative was put forward by Riad Seif, a veteran Syrian opposition figure who has emerged as a strong candidate to lead a transitional government in Syria.

U.S. officials say he is among hundreds of opposition figures that U.S. diplomats have been impressed with in discussions during the Syrian crisis. The 66-year-old Seif, who suffers from cancer, is a former reformist lawmaker and businessman who spent years in Syrian prisons before the uprising began and is widely seen as a charismatic figure who can help put the country back together again.

He was beaten up by security forces at a protest in October last year before he finally left the country, where he has been quietly working with various opposition groups.

"Syria is in desperate need of strong leadership that is cooperative and inclusive, a leadership that responds to the needs of the revolution and our steadfast people," Seif wrote in the proposed initiative. "This leadership framework will represent the revolution and its goals."

In addition to the leadership body, the proposal would establish a military council, a judicial committee and a transitional government to be made up of technocrats.

A number of opposition groups are staying away from the conference, including the National Coordination Body, a rival to the SNC, and the National Democratic Front headed by veteran opposition leader Michel Kilo.

They complain of being sidelined and describe the SNC as a group of dictators no worse than Assad.

"Nobody can build a house alone and then invite the others to stay in the servants' room," said Haitham Manna, a Paris-based veteran dissident who heads the National Coordination Body's external branch. He said any unilateral decision at Doha to form a transitional government will only serve to fragment the opposition even more.


Karam reported from Beirut. Associated Press writers Abdullah Rebhy in Doha, Qatar, Matthew Lee in Washington and Ayse Wieting in Istanbul contributed to this report.