Peace envoy Lakhdar Brahimi met internal opposition groups Tuesday as he pushed a new initiative to end Syria's conflict, and as Gulf Arab states urged a rapid political transition.
AFP reported that Brahimi, the UN-Arab League's special envoy to Syria, held talks at his Damascus hotel with a six-strong delegation led by Hassan Abdel Azim, head of the National Coordination Committee for Democratic Change, an opposition group tolerated by the regime.
Azim said afterwards that Brahimi would stay in Syria until Sunday "to try to implement an international consensus to end the crisis."
His deputy Raja Nasser told reporters, according to AFP, "The only solution is a transitional government that holds all powers.
"A political solution is the only solution, and this means the establishment of a new democratic regime instead of the current regime," said Nasser.
A French daily has reported a supposed U.S.-Russian initiative for a transition in Syria, causing rage among opponents who reject any compromise with the regime.
Le Figaro said a solution in the offing would involve keeping Assad in power until 2014 while preventing him from further renewing his mandate.
The Local Coordination Committees, a grassroots network of anti-regime activists, blasted Brahimi and the international community for failing to stop the bloodshed.
At least another 113 people were killed across Syria on Tuesday, including 45 civilians, according to the Syrian Observatory for Human Rights.
In total, more than 44,000 people have been killed since the uprising erupted in March last year, the Observatory estimates.
"Brahimi's arrival in Damascus to discuss a new political initiative to solve the crisis caused by the regime... has not put a stop... to massacres," the LCC said, according to AFP.
It said the LCC rejects "any initiative that puts Syrians in a position where they are extorted and forced to choose between accepting unfair compromises, or the continuation of the regime's crimes against them."
The opposition Muslim Brotherhood also dismissed any compromise that would leave Assad in power.
"We consider that giving Assad the opportunity to commit an endless string of crimes is tantamount to complicity in these crimes," it said.
Brahimi met Assad on Monday, saying afterwards that they had "exchanged views on the many steps to be taken in the future" regarding the "always worrying" Syrian crisis.
A diplomat at the United Nations said that there was no sign of a breakthrough, with Assad appearing unready to negotiate and the armed opposition ruling out a compromise.
"Assad appears to have stonewalled Brahimi again, the UN Security Council is not even close to showing the envoy the kind of support he needs and the rebels will not now compromise," said the diplomat.
Meanwhile, violence raged southwest of Damascus, mainly in the towns of Moadamiyet al-Sham and Daraya, the Observatory said, adding at least eight people were "summarily executed" by regime forces.
Rebels seized the town of Harem in the northwestern province of Idlib, large swathes of which are now in the hands of anti-regime fighters, it added.
In the northern city of Aleppo, warplanes attacked a rebel-occupied school in the Tareq al-Bab area, said the Observatory which relies on a network of activists and medics for its information.
On Sunday, an air strike by the Syrian government in the town of Halfaya killed dozens of people.
Most of the victims were people who had been standing in line for bread at a bakery, in a crowd that was estimated at about 1,000.
Meanwhile, reports of the use of chemical weapons by Assad's troops against the rebels have become more frequent recently.
Al Jazeera reported on Monday that Assad had dropped bombs containing toxic gases, killing six people and blinding others in Homs. Opposition forces released a video showing a victim struggling to breathe after the attack.
Doctors have said that Assad’s forces are probably also using “Agent 15,” which causes paralysis.