Regime troops killed at least 21 people in a blistering assault on a central village on Sunday, a watchdog said, while twin blasts rocked Damascus and Syria's second city Aleppo was hit by air strikes.
As the violence raged, new international peace envoy Lakhdar Brahimi said change in Syria was "unavoidable," although he carefully refrained from calling for Assad to step down, as his predecessor Kofi Annan had.
The Syrian Observatory for Human Rights said it expected the death toll to mount from the army offensive on Al-Fan village in Hama province, one of the main arenas of conflict in the more than 17-month uprising against President Bashar al-Assad.
The Britain-based watchdog had no details on whether those killed were civilians or rebel fighters, "but all 21 of the dead were men," said its director Rami Abdel Rahman.
Horrific images shot and posted on YouTube by activists in Al-Fan showed a long row of bodies shrouded in white cloths, laid out on the ground surrounded by scores of weeping men, women and children.
State news agency SANA said all of those killed during the Al-Fan clashes were from "an armed terrorist group that was attacking citizens and security forces."
A picture released by the Syrian Arab News Agency shows a member of the Syrian security forces inspecting the wreckage of a vehicle in the Abu Remmaneh district of the Syrian capital Damascus. Regime troops killed at least 21 people in a blistering assault on a central village on Sunday, a watchdog said, while twin blasts rocked Damascus and Syria's second city Aleppo was hit by air strikes.
In Damascus, twin bombs exploded near a tightly guarded government compound in the heart of the city, wounding four people, state television said.
The bombings struck in Abu Remmaneh district where security buildings and the office of Vice President Faruq al-Shara are located, the television said, blaming "terrorists."
They were among at least 168 people killed on Saturday -- 110 civilians, 32 soldiers and 26 rebels, the Observatory said. The watchdog gave a preliminary toll of 66 people killed on Sunday -- 51 civilians, 12 soldiers and three rebels.
Shara is the highest-ranking Sunni Muslim in Assad's minority Alawite-led government and was the subject of repeated defection rumours last month before he made a public appearance during a visit by a senior envoy from key ally Iran.
The Ahfad al-Rasul (Grandchildren of the Prophet) brigade of the rebel Free Syrian Army claimed responsibility for the attack, also threatening to attack Assad's palace.
State media reported Sunday that a car bomb blast killed 15 people the previous day near a mosque at Sbeneh, a poor neighbourhood on the capital's southern outskirts.
-- 'Change necessary': new envoy --
Near Aleppo, another key battleground in the conflict, an AFP correspondent said air strikes were carried out on a residential area of Al-Bab, a rebel rear base north of Syria's second city.
Map locating the latest flashpoints in the Syrian conflict
Columns of smoke rose from the entrance to Aleppo itself, where fighting was reported to have been limited to a handful of neighbourhoods of the city, scene of a key battle for more than five weeks.
Elsewhere, shelling of Qusayr destroyed the last working bakery in the rebel-held part of the central town, activists said, aggravating a growing food shortage.
Rights watchdogs have expressed growing concern about deteriorating conditions in areas under a protracted army siege, including parts of Aleppo and third city Homs.
"The shelling of Hanano did not stop from midnight until 5:00 am," an activist told AFP from the pro-opposition northeastern district of Aleppo, scene of fierce fighting since July 20.
Brahimi, who took over as international peace envoy on Saturday, told Al-Jazeera that "change is necessary, indispensable, unavoidable."
He said his position was to engage all the parties and he would not be drawn on Assad's future.
"It is too early to speak about who should go and who should stay," he told the channel.
"This is not a step backwards. Mr Assad is there and is the president of the present government," he said. "Kofi talked to him, and I will talk to him."
The new international peace envoy to Syria, Lakhdar Brahimi, has said change is "unavoidable."
Similar comments by the veteran Algerian diplomat soon after his nomination last month drew an angry reaction from Syria's exiled opposition, which accused him of giving Assad's regime a "licence to kill."
Brahimi, who will formally take the reins in handover ceremony with Annan and UN chief Ban Ki-moon on Tuesday, has been holding meetings at the UN headquarters in New York.
He takes over amid mounting pessimism about the prospects for peace after Annan announced he was stepping down last month, blaming divisions in the international community for the failure of his April six-point peace plan.
The main opposition Syrian National Council, meanwhile, has agreed to expand to include more groups opposing Assad and will reform to be more representative, a spokesman told AFP.
At a meeting in Stockholm late Saturday, the SNC agreed to expand its membership and to hold a vote later this month to elect its leadership, spokesman George Sabra said.
The move follows criticism from both within and outside the group that it is failing to unite the diverse opposition forces working against Assad, after more than 17 months of brutal conflict.
The violence has since intensified with August much the bloodiest month of a conflict that has killed more than 26,000 people, according to Syrian Observatory figures.