"The only way to succeed in Syria is to sit down at the table to launch a national dialogue," Zohbi said. "The opposition must accept the choice of dialogue and... the army, by facing down terrorism, is protecting this dialogue."
Forces loyal to President Bashar al-Assad suffered a new blow, however, as two suicide car bombings tore through an officers' club in the southern city of Daraa, cradle of the nearly 20-month uprising.
The attacks killed 20 soldiers and possibly many more, said the Syrian Observatory for Human Rights.
"The two bombings were the result of suicide attacks, carried out by two men who drove vehicles loaded with explosives into the garden a few minutes apart," Observatory director Rami Abdel Rahman said.
State news agency SANA reported that three car bombings killed seven people and wounded many, but did not say they were at a military position.
It also said a car bomb had wounded nine people in the southern Damascus neighbourhood of Daf al-Shawk, while state television said a rocket wounded two girls in the capital's Christian district of George Khoury.
Elsewhere, the army retook a stretch of the Damascus-Aleppo highway used to send its reinforcements to main northern battlefields, said the Observatory.
Regime forces had "gradually advanced over the past 10 days to regain control of several villages that fell in (early) October to the rebels to the west of the Damascus-Aleppo highway," Abdel Rahman told AFP.
But the army had so far failed to enter the strategic rebel-held town of Maaret al-Numan, where fighting intensified after soldiers in the besieged nearby military base of Wadi Deif received supplies.
-- SNC under pressure --
In Doha, the SNC -- once seen as the leading representative of the opposition but now seen in Washington as dominated by out-of-touch exiles -- came under increasing pressure to accept a unity plan.
"We have started an open dialogue with our brothers and looked at their initiative," the SNC's new leader George Sabra said. "But we have our own point of view and our own ideas that we plan to put forward."
The SNC had already twice asked for a postponement of the talks on plans for a broad-based government-in-waiting.
Its counter-proposal envisages the formation of a provisional government pending a general congress of the opposition, according to a document seen by AFP.
The existing plan, inspired by Riad Seif who is reportedly seen by Washington as a potential new opposition chief, envisages the formation of a transitional government, a military council to oversee rebel groups and a judiciary to operate in rebel-held areas.
"The SNC is older than... any other initiative" on the table, Sabra told reporters, adding no opposition group should be forced under the banner of another.
Senior SNC official Ahmad Ramadan said: "We are being submitted to pressure to accept being part of a new formation, in exchange for international promises but with no guarantees."
Ramadan suggested it would be "difficult to reach an agreement today" (Saturday), but added the meeting may come up with a "declaration of principles" in order not to end in failure.
But former SNC chief Burhan Ghalioun told reporters he was optimistic.
"The meeting is still on, but there has been real progress. There will be a political agreement for common action, a political body to supervise military action," he said.
The army on Saturday destroyed a ship carrying armed rebels on the Euphrates River in the northeast, SANA said, the first time state media has reported such an incident on the river that runs from Turkey through Syria and Iraq.
Also near Turkey, Kurds backed by militia took control of three northeastern towns in two days after urging pro-government forces to leave, said the Observatory.
The watchdog said at least 101 people were killed across Syria on Saturday -- 41 soldiers, 34 civilians and 26 rebels.
It says more than 37,000 people have died since the uprising erupted in March 2011, first as a protest movement and then as an armed rebellion after demonstrations were crushed.