The UN-Arab League envoy for Syria says peace talks are in doubt unless a "credible opposition" takes part, overcoming rifts among its factions, as dozens are killed in a truck bombing in the Syrian city of Hama.
Lakhdar Brahimi refused to give a firm date for a new round of talks in Geneva as he spoke to reporters in Cairo on Sunday alongside Arab League chief Nabil al-Arabi, who had said preparations were under way for November 23.
Brahimi cautioned that the meeting would only go ahead in the presence of a "credible opposition representing an important segment of the Syrian people" opposed to President Bashar al-Assad.
"There is an agreement to attempt to hold Geneva 2 in November, but the date has not been officially set," he said. "The final date of the conference will be announced at a later time... and we hope it will take place in November."
Both officials acknowledged the obstacles to a peace conference as Arab and Western diplomats – including US secretary of state John Kerry – were preparing for a Friends of Syria meeting with opposition leaders on Tuesday in London.
Brahimi is on the first leg of a Middle East tour aimed at drumming up support for the initiative to end the 31-month conflict that has killed more than 115,000 people.
The veteran troubleshooter said he would also travel to Qatar, Turkey, Iran, Syria and then Geneva for talks with Russian and US representatives.
Al-Watan, a pro-Damascus newspaper, said Brahimi would visit Syria next week.
Washington and Moscow have been trying to organise the conference on the heels of a landmark deal they reached for Syria to destroy its chemical weapons by mid-2014.
The Geneva initiative was first announced last year, but it has been repeatedly postponed amid opposition wrangling and a dispute over which countries, including Iran, should participate.
Syria has heavily criticised Brahimi, especially after he suggested a transitional government be set up and given full powers until elections, following his last visit in late 2012.
Al-Watan said Damascus was ready to welcome him as long as "he works as a mediator, not as a party in the international conflict over Syria".
But Syria has consistently refused to enter negotiations that demand Assad quit power as a condition.
Meanwhile, the National Coalition umbrella opposition group said its members would decide in the coming days whether to attend the Geneva talks, while the Syrian National Council, a key component of the bloc, has threatened to quit if they do.
But even if the Coalition attends the Geneva meeting, it is unclear whether it can enforce any agreement, after dozens of rebel brigades have in recent weeks rejected the umbrella group.
Truck bomb targets regime troops
On the ground, a truck bomb killed at least 43 people – including 32 civilians – in the regime-held central city of Hama, said the Syrian Observatory for Human Rights.
State media put the toll at 37, including two children.
The Observatory said a man detonated the truck laden with explosives at a checkpoint near an agricultural vehicles company on the road linking Hama to Salamiyeh, and that regime troops were among the dead.
Assad's father and predecessor Hafez al-Assad brutally put down a Muslim Brotherhood uprising in Hama city in 1982, killing between 10,000 and 40,000 people.
Sunday's attack came a day after rebels from the Al-Nusra Front, a jihadist group linked to Al-Qaeda, set off a car bomb and launched a an assault on a checkpoint near Damascus, killing 16 soldiers.
UN humanitarian chief Valerie Amos has called for a ceasefire in the embattled Damascus suburb Moadamiyet al-Sham, where thousands of people "remain trapped".
The southwestern district was one of a number of suburbs hit in an August 21 sarin gas attack, blamed by the opposition on the regime, which led to the deal to dismantle Syria's chemical arsenal.
In the north, the air force carried out new strikes on rebels around Aleppo central prison, which they are trying to wrest from government control, said the Observatory.