Syrian opposition leaders struck a hard-won deal on Sunday under intense international pressure to form a broad, new coalition to prepare for the fall of President Bashar al-Assad.
Delegates, who had struggled for days in the Qatari capital Doha to find the unity their Western and Arab backers have long urged, said the new body would ensure a voice for religious and ethnic minorities and for the rebels fighting on the ground, who have complained of being overlooked by exiled dissident groups.
Some details remain outstanding, including who will head the new Syrian National Coalition for Opposition and Revolutionary Forces and the final assent of some leaders not present in Doha.
Diplomats and officials from the United States and Qatar, the tiny Gulf emirate whose oil and gas wealth has helped fund the 20-month-old uprising, have particularly been pressing the Syrian National Council (SNC), whose leaders mostly live abroad, to drop fierce objections to joining a wider body.
"An initial deal has been signed. A final formulation has been agreed and signed," Ali Sadreddine al-Bayanouni, a delegate for the Islamist group the Muslim Brotherhood, told reporters.
"The evening session will be for electing the president of the body and his deputy," he added. The meeting was due to resume around 6 p.m. (1500 GMT).
Delegates said there would be specific representation for women and ethnic Kurds as well as for Christians and Alawites, the religious minority to which Assad belongs and from which he has drawn much of the leadership of his security forces.
It was not entirely clear whether full agreement had been reached, however.
Some delegates had to refer back to leaders who were absent: "Everybody agreed to sign," said Bassem Said Ishak of the SNC. "But the Kurds need 48 hours to get approval from their leadership."
The Coalition's president, once chosen, will automatically become the focal point for opposition activities in a rapidly developing conflict in which Washington and its allies have been concerned that a sudden collapse of Assad's rule could see anti-Western militants benefit from chaos to seize control of a large and pivotal country at the heart of the Middle East.
The SNC, which elected its own new leader, George Sabra, on Friday, had lost the confidence of Washington and other powers, who saw it as unable to provide overall direction for the anti-Assad forces and riven with personal disputes.
In marathon talks that lasted into the early hours of Sunday in Doha, the SNC had threatened to pull out of the initiative altogether. Qatar's prime minister and the foreign minister of the United Arab Emirates came personally to try to persuade them, insisting that a deal would secure international backing.
"The SNC agreed only under pressure. They only want to monopolize representing the revolution," one source at the meetings said. "They were given a deadline of 10 a.m. today to either come join or risk it being announced without them."
Delegates said privately that Riad Seif, an influential businessman and SNC member who first presented the U.S.-backed unity initiative had been a possible candidate to head the body. But he has said he is unwell and not interested in the post.
Under the agreement outlined in Doha, the SNC will be among groups to have seats in an assembly of 55 to 60 members under a president, two deputies and a secretary general, all of whom may be elected later on Sunday. People close to Seif said the SNC will have 14 seats but SNC sources said their group expected 20.
SNC member Wael Merza said a number of consensus candidates were already likely to gain seats. These included leftist Haytham al-Maleh, the Muslim Brotherhood's Bayanouni, independent Islamists Munzer al-Khatib and AbdulKareem Bakkar and a noted opposition activist, Suhair al-Atassi.
Merza said the Kurdish National Council and a prominent Alawite, Munzer Makhous, would have places on the assembly, as would local representatives of Syria's 14 provinces.
"We are open to all the real opposition powers that have weight, influence and the same aims as the Coalition to bring down the regime and establish a democratic Syria," Merza told Reuters. "It is not a closed club."
The SNC's leadership repeatedly rejected criticisms over the past week in Doha, saying the body was reforming internally, holding its first leadership election - as opposed to appointing leaders as in the past - and bringing in more youth activists.
But some Council members quit over what they said was Islamist domination of the SNC and the failure of women to win any seats on its general secretariat in voting last week.
However, the Muslim Brotherhood - which has around 25 percent of the SNC general secretariat - and other Islamists allied to them, gave support to Seif's unity initiative.
Delegates said the coalition would try to form a 10-member transitional government in the coming weeks - along the lines of Libya's Transitional National Council, which was formed during last year's uprising and took power when Muammar Gaddafi fell.
The Arab League is expected to allow the group to take over Syria's representation on that inter-governmental body - from which Assad was suspended. Efforts to win wider international recognition, including at the United Nations , could follow.
The SNC had sought guarantees that such international recognition should come first before agreeing to form the new coalition. Its new leader, Sabra, had said on Saturday that foreign powers should focus on providing arms to rebels rather than prodding the SNC to submerge itself in a new organization.
Robert Ford, the U.S. ambassador for Syria, told SNC members bluntly last week that they should forget dreams of U.S. military intervention in President Barack Obama's second term.
Rebels have been at the mercy of Assad's air force, putting them at a critical strategic disadvantage. Protests for democratic reform broke out 20 months ago, meeting a violent response which led to a conflict that has cost more than 38,000 lives and threatens to spill into neighboring countries.
(Additional reporting by Regan Doherty; Writing by Andrew Hammond; Editing by Alastair Macdonald)