Syria's main opposition bloc, under US pressure to reshape into a widely representative government-in-exile, agreed on Monday to broaden its structure to accommodate 13 other groups, a spokesman said.
The decision by the Syrian National Council came on the second day of a four-day meeting of opposition groups in the Qatari capital Doha aimed at forging a more united front against Syrian President Bashar al-Assad's regime.
Participants "have agreed a restructuring plan and to reduce the number of (current) members of the general secretariat to accommodate 200 new members representing 13 political groups and independents," said SNC spokesman Ahmad Kamel.
Kamel said the existing membership would be reduced from 313 to 220 to pave the way for the additional 200 members. The general secretariat will convene in its revamped form on Tuesday, he added.
The meeting is also expected to discuss an initiative by leading dissident Riad Seif, which seems to enjoy US support but has encountered reservations from some SNC members, to unite all Syrian groups opposed to Assad.
The initiative will top the agenda of a broader meeting on Thursday called by host Qatar and the Arab League.
"We will form a political leadership that will in turn form a government of technocrats," Seif said on Sunday, insisting that his proposal is "not to replace the SNC which should be an important component."
Qatari Prime Minister Sheikh Hamad bin Jassem al-Thani said that his government will back any agreement reached by the Syrian opposition factions but insisted that they must now unite.
"We will support what the Syrian people agree on. I think the meeting in Doha is very important. I think everybody is waiting to see an agreement between all the Syrian opposition," he told reporters in Addis Ababa.
"Part of the problem now is that we have many oppositions ... The time now is to be united... and we need one address for the opposition," he said.
Seif and some two dozen Syrian opposition figures who gathered in Amman on Thursday came up with proposals for a new body to represent the disparate groups opposing Assad.
Among those in attendance were some SNC members, former premier Riad Hijab who defected in August, Ali Sadreddin Bayanuni of the Muslim Brotherhood and Kurdish and tribal representatives.
The SNC hit back at US criticism on Friday, accusing Washington of undermining the revolt and "sowing the seeds of division."
US Secretary of State Hillary Clinton had called the bloc unrepresentative of opposition forces on the ground and said it "can no longer be viewed as the visible leader of the opposition."
The SNC has sought to be the interlocutor between the international community and forces opposed to the Assad regime since its formation six months after the start of the uprising in March last year.
But divisions have dogged opposition ranks. Some groups strongly oppose the armed struggle being waged by the rebel Free Syrian Army against government troops with the backing of the SNC.
Russian Foreign Minister Sergei Lavrov criticised Western and Gulf Arab countries for failing to use their influence with the rebels encourage them to "sit at the negotiating table."
Some foreign governments preferred to "unify the rebels not on the basis of negotiations but on the basis of continuing the fighting," he told a Cairo news conference.
Assad's government accuses Qatar and Saudi Arabia of channelling weapons to the rebels through Turkey with Western blessing.
Russia and China have repeatedly blocked Western- and Arab-backed efforts for tougher action against Assad's regime at the UN Security Council.