Soldiers loyal to Syria's President Bashar al-Assad raise their weapons while carrying pictures of him at Sbeineh town, southern Damascus, after they took control of it from rebel fighters last week. (SANA/REUTERS)

A string of Syrian government gains in the Damascus suburbs and mounting pressure on rebels in the northern part of the country are likely to complicate Western efforts to persuade the opposition to attend planned peace talks, analysts say.

Five towns south of Damascus, Syria’s capital, have fallen into army hands in the past 10 days, according to rebels. In the north, a rebel commander was killed in Aleppo, where the opposition was forced to issue an order this week for all armed groups to mobilize at the front lines.

After more than 21 / 2 years of conflict, the United States, Russia and the United Nations are scrambling to bring the two sides to the negotiating table in Geneva before the end of the year. But both the political opposition and its armed forces have outlined preconditions for talks.

Analysts say the government gains will make the task of getting the opposition to participate even more difficult, because the rebels will be unlikely to want to negotiate while they are on the back foot militarily.

“Whenever there is any international diplomatic effort, the regime tries to make more military advances,” said Musab Abu Qatada, spokesman for the rebel military council in Damascus.

Clashes continued Friday on the farms around Hujeira, which on Wednesday became the latest suburb to fall. Abu Qatada said the string of defeats, in which rebels lost more than 50 fighters, leave them more vulnerable in the besieged suburbs of Moadamiya, to the west, and Eastern Ghouta.

The opposition also says that the deal for Syria to hand over its chemical weapons has shifted focus as President Bashar al-
Assad’s government continues to crush rebel-held areas, hemming them in and cutting food supplies.

The Hague-based Organization for the Prohibition of Chemical Weapons met Friday to finalize a plan for the destruction of about 1,300 tons of Syrian chemical weapons and precursors. One issue is where the work would be carried out. In a setback late in the day, Albania, after protests outside its parliament, rejected a request from the United States to provide a site.

While the Syrian opposition concedes that the government — backed by forces from the Lebanese Shiite group Hezbollah — is making small but steady gains near the capital and in the central province of Homs, it claims to be repelling advances in Aleppo, including in the vicinity of the airport.

After the army pushed forward last week, rebel groups, including the powerful Tawhid Brigade and al-Qaeda-linked Jabhat al-Nusra, issued an emergency call Monday for all armed formations to join the front lines.

In a blow to the rebels’ efforts, Abdul Qader Saleh, the leader of Tawhid, was wounded in an air raid in Aleppo province Thursday. He was recovering Friday in a Turkish hospital. Youssef al-
Abbas, whom the British-based Syrian Observatory for Human Rights described as Tawhid’s finance chief, was killed in the air raid, rebels and activists said.

“The government certainly feels as though it has a certain amount of momentum,” said Salman Shaikh, director of the Brookings Doha Center. “I think its main plan is to fortify Damascus and its heartland, while also attracting fighters to the north. It will complicate efforts by international players to engage with some of these groups and persuade them not to veto [the planned talks in] Geneva. They will be more willing to fight it out.”

Ahmed Ramadan contributed to this report.