Syrian jets hammered a rebel town on Friday on the second day of an assault in which the regime is accused of using cluster bombs, as peace envoy Lakhdar Brahimi landed in Damascus to press for a truce.
Brahimi is bidding to secure a ceasefire during a four-day Muslim holiday from October 26, hoping it will bring a longer cessation in the 19-month conflict that has already killed more than 34,000 people.
"We will have discussions here with the government, the political parties and civil society about the situation in Syria," Brahimi told journalists at Damascus airport.
"We will talk about the need to reduce the current violence and about whether it is possible to stop for the occasion of Eid al-Adha," he said about next week's Muslim holiday.
Violence has persisted, however, with rebels and loyalists of President Bashar al-Assad locked in battle for the northwestern town of Maaret al-Numan on the Damascus-Aleppo highway linking Syria's two biggest cities.
Assad's forces, who hold air supremacy, again battered the town a day after strikes on a residential area killed dozens, nearly half of them children, rescuers told an AFP reporter at the scene.
The military wants to regain control of the highway to resupply units under fire in Aleppo for the past three months, and assist 250 troops besieged in their Wadi Deif base.
Fighter jets overflew at high altitude before nosediving and striking targets on the town's outskirts, as helicopter gunships buzzed the area, the correspondent said.
The Syrian Observatory for Human Rights said the aircraft concentrated their firepower on rebel camps near Wadi Deif, also a major storage facility for armour and fuel.
Rebels showed AFP debris from cluster bombs which they accused the air force of dropping on residential areas, as well as dozens of other bomblets that failed to explode on impact.
Human Rights Watch has accused Syria of using cluster bombs, a charge denied by the military which insists it does not possess them.
On Friday, the army opened fire and launched tear gas bombs against anti-regime protesters in the central city of Hama, said the Britain-based Syrian Observatory.
Following the weekly Muslim prayers, hundreds of demonstration took to the streets in several towns and cities.
"United States, your malice has not had enough of our blood," was the protesters' rallying cry this week, according to the Syrian Revolution 2011 Facebook page.
Syrian activists have long condemned the international community for its failure to take action against Assad's regime.
In the Maaret al-Numan area, the rebels said on Thursday they had launched a "final assault" on the nearby army base of Wadi Deif, which is reportedly surrounded by about 2,500 insurgents.
They responded to the air strikes by opening fire from heavy machineguns mounted on pickup trucks. "It doesn't matter if we die. We must shoot down these planes," one said.
Fighter jets targeting residential areas of Maaret al-Numan on Thursday killed at least 49 people, among them 23 children, rescuers said.
The strikes destroyed two housing complexes and a mosque, where many women and children had taken refuge, with bodies still trapped under the rubble of the mosque, medics and rescuers said.
Among those killed was a nine-month-old baby.
Brahimi was received at Damascus airport by Syria's deputy foreign minister, Faisal Muqdad, and was scheduled to meet Foreign Minister Walid Muallem on Saturday. He is expected to hold talks with Assad at a later date.
Damascus says it is ready to discuss the ceasefire proposal with Brahimi. The opposition says it would welcome any truce but insists the regime must first halt its daily bombardments.
In the latest cross-border incident, Turkish artillery struck back at Syria on Friday after two Syrian shells landed on the country's territory, Turkey's state-run television TRT reported.
The television network said the shells fell into an empty field in Hatay province near the Syrian border. There was no report of casualties.
Turkey has been retaliating systematically on each occasion that its border with Syria has been breached by mortar bombs or shells since Syrian fire killed five Turks on October 3.
The Syrian conflict began in March 2011 with pro-reform protests but turned into a civil war pitting mainly Sunni Muslim rebels against Assad's regime dominated by his minority Alawite sect, an offshoot of Shiite Islam.