The coalition, whose official name is the National Coalition of Syrian Revolutionary and Opposition Forces, was formed at a meeting in Qatar this month and has been recognized by Britain, France, Turkey and the Gulf Cooperation Council. To win further support from foreign capitals, it must tackle the broader problems of uniting the many opposition groups in exile and the rebels on the ground in Syria.
Delegates were expected to hold their second day of talks in a Cairo hotel on Thursday against the backdrop of a 20-month civil war in which about 40,000 people have been killed in clashes between armed rebels and jihadist fighters on one side and Mr. Assad’s forces on the other. The rebels appear to be gaining in their strategy to challenge the air supremacy of Mr. Assad’s military.
There were reports on Wednesday that for the second successive day, insurgents had shot down a government aircraft. Video posted on the Internet by rebels showed an airplane tail assembly jutting out of debris. Such videos are difficult to verify, but the episode on Wednesday seemed to be confirmed by other witnesses.
“We watched a Syrian plane being shot down as it was flying low to drop bombs” on the town of Daret Azzeh, 20 miles west of Aleppo and close to the Turkish border, said Ugur Cuneydioglu, who said he saw the aircraft being downed from a Turkish border village in southern Hatay Province. “It slowly went down in flames before it hit the ground. It was quite a scene,” Mr. Cuneydioglu said.
The video said the plane had been brought down by “the free men of Daret Azzeh soldiers of God brigade.”
On Tuesday, Syrian rebels said they shot down a military helicopter with a surface-to-air missile outside Aleppo.
The violence on Wednesday also included car bombs in a Damascus suburb that killed dozens of people.
In their first meeting since their umbrella organization was created in Doha, Qatar, on Nov. 11, coalition delegates confronted the realities of the political terrain. Disagreements emerged over the coalition’s composition when one member, the Syrian National Council, tried to increase the number of its representatives.
“Nothing will proceed until we work this out,” said one council member who spoke on condition of anonymity, according to Reuters.
The focus also seemed to be more on deciding how leadership candidates should be chosen rather than on who they might be. “I don’t think we’ll be discussing the election of a transitional government during the meeting today,” said Khaled Khoja, a coalition member. “We’re still discussing whether to have a government or to have committees instead.”
While the group, and the talks, are in their infancy, members appeared to recognize that world supporters were watching for results. Mr. Khoja said that while the group was discussing the coalition’s structure, it wanted to “see the outcome of the meeting in Morocco before deciding on the government.”
He was referring to a meeting planned for next month in Morocco of the so-called Friends of Syria group of nations, which includes the United States. At a meeting in New York City in September that included foreign ministers and Syrian opposition leaders, the group offered modest pledges of support for opponents of the Assad government. The opposition had unified under international pressure to give provinces better representation, and ideally, to oversee the disparate rebel factions while also providing a counterweight to the well-armed jihadist groups in the country.
The conflict has also flared along Syria’s borders with Lebanon, Israel, Turkey and Jordan.
In Turkey, which was once an ally of the Assad government, a team of NATO inspectors visited sites on Wednesday where the alliance might install batteries of Patriot antiaircraft missiles.
Another video on Wednesday showed a rebel fighter holding what appeared to be a complete SA-16 heat-seeking, shoulder-fired missile.
The man claimed to have shot down both the airplane and the helicopter, and said the missiles had been captured by rebels when they overran Base 46 outside Aleppo earlier this month.
High-profile tactical successes in the war have often been followed by videotaped claims of responsibility, and in part are seen as fund-raising opportunities for the fighters. Many claims, including those by the rebel fighters, are impossible to verify immediately.
But it was significant. The SA-16 is more modern and capable than the more commonly seen SA-7. It flies at a faster speed, can be used against aircraft at much wider range of attack angles, has a longer range and is promoted by its Russian exporters as being more resistant to an aircraft’s efforts to thwart it.
Its presence suggested that the rebels have been acquiring more weapons and could be mounting a more meaningful challenge to the Syrian Air Force.
State news media said on Wednesday that two car bombings struck Jaramana, a suburb of Damascus that is populated by members of the Christian and Druse minorities.
The SANA news agency said the death toll was at least 34. An activist group based in Britain, the Syrian Observatory for Human Rights, said 47 people were killed.
Christine Hauser reported from New York, and Hala Droubi from Dubai, United Arab Emirates. Reporting was contributed by Alan Cowell from London; Sebnem Arsu from Istanbul; Hania Mourtada from Beirut, Lebanon; and C. J. Chivers from the United States.
