DOHA, Qatar — Sharp disagreements arose Sunday on the first day of a Syrian opposition conference meant to forge a more cohesive leadership that the international community says is necessary before it will boost its support for those trying to overthrow President Bashar Assad.
The main opposition group in exile, the Syrian National Council, balked at a US-backed plan that would largely sideline it to make room in a new leadership council for fighters and activists inside Syria.
However, with international pressure mounting, the National Council also suggested it is willing to negotiate a compromise that would give the council more influence in a new leadership team.
The international community has long urged the National Council, widely seen as dysfunctional and out of touch, to broaden its base and include a greater spectrum of Syrian society, especially those fighting inside the country. Last week, Secretary of State Hillary Rodham Clinton was unusually harsh, suggesting the that the National Council’s leadership days are over.
As opposition leaders haggled in Qatar, activists said that rebels captured an oil field in eastern Syria on Sunday after three days of fighting with government troops, and that they shot down a Syrian warplane in the area.
The Britain-based Syrian Observatory for Human Rights said rebels overran the Al-Ward oilfield in the province of Deir el-Zour near Iraq.
Oil was a major source of revenue for Assad’s regime before the United States and the European Union imposed an embargo on Syria’s crude exports last year, in response to Assad’s brutal crackdown on the uprising against him. Syrian officials have accused rebel units of targeting the country’s infrastructure, including blowing up the oil and gas pipelines.
Syrian state media, meanwhile, said rebels detonated a car bomb near the Dama Rose hotel in the capital, wounding several people. The hotel had been used in the past by UN observers visiting Syria.
The reports also said rebels were behind the assassination of a leading member of the ruling Ba’ath party in northeast Raqqa province.
The Syrian opposition leaders met at a luxury hotel in Doha, the capital of the small Gulf state of Qatar that has emerged as a major backer of the Syrian rebels. Organizers said more than 400 delegates are attending four days of internal Syrian National Council meetings and will choose new leaders on Tuesday. A day later, the council is to vote on the leadership plan proposed by Riad Seif, a prominent activist.
On Thursday, Seif will attempt to form the new leadership group with the backing of the council. If he is successful, the Friends of Syria, an alliance of countries backing the rebels, is to convene in Morocco, he said.
Failure to reach a deal in Doha could further heighten tensions between Syria’s political opposition and the international community.
Opposition leaders feel abandoned by the United States and other foreign backers, saying they are not providing the money and weapons the rebels need to defeat Assad in a stalemated civil war. Washington and others say they can’t step up aid unless the opposition stops bickering and establishes a more representative — and unified — leadership.
The revolt erupted nearly 20 months ago as a peaceful uprising that escalated into a civil war and has claimed more than 36,000 lives, according to a tally by activists.
At the conference in Doha, the National Council is considering whether to accept Seif’s plan to set up a new leadership group of about 50 members. The council would get some 15 seats, meaning its influence would be diluted, while military commanders and local leaders in rebel-held areas would win wider representation.
Seif said his plan has broad international backing and portrayed it as a stepping stone to more robust foreign aid.
Syrian National Council chief Abdelbaset Sieda dismissed Seif’s optimism, saying he and others in the council no longer trust promises of international support that are linked to restructuring of the opposition.
The council is to decide Wednesday whether to accept Seif’s plan. Sieda said the council believes it deserves at least 40 percent of the seats, should it decide to join the new group, suggesting the group may have decided it’s under too much pressure to reject the plan entirely.
In Cairo, Lakhdar Brahimi, the UN-Arab League envoy to Syria, met with Russian Foreign Minister Sergey Lavrov, but they differed in their assessments. Brahimi called the situation ‘‘deplorable,’’ adding, ‘‘The solution will either be a political one that all sides agree on, or the future of Syria is very bad.’’
Lavrov blamed the Syrian opposition for not accepting a cease-fire proposal that left the door open for a transitional period with Assad still in power.
The Seif, who left Syria few months ago after having been detained by the regime, said that if his plan is accepted, ‘‘the whole world will be behind’’ the new opposition leadership. Seif, 66, has cancer and is not seeking a leadership role.