Syria said it is ready to discuss the departure of President Bashar al-Assad as part of a negotiated settlement to the increasingly ferocious conflict but the US reacted with scepticism.
The surprise comments Tuesday by a Syrian envoy visiting Moscow emerged after Russia bluntly told the West not to meddle in Syria in the wake of US President Barack Obama's warning to Damascus over its chemical weapons arsenal.
In Syria, at least 198 people were killed nationwide on Tuesday, a watchdog said, reporting relentless shelling and fighting across swathes of the main battleground of Aleppo and many deaths in a bloody raid on a Damascus suburb.
"As far as his resignation goes -- making the resignation itself a condition for holding dialogue means that you will never be able to reach this dialogue," Syrian Deputy Prime Minister Qadri Jamil said after talks in Moscow.
But he added: "Any problems can be discussed during negotiations. We are even ready to discuss this issue."
According to political sources in Damascus, Jamil was sent to Moscow to discuss a possible plan for a presidential election in Syria in which all candidates would be allowed to stand, including Assad.
The exiled opposition umbrella group the Syrian National Council said it was studying the formation of a transitional government, but did not elaborate on whether it could include regime figures.
And the United States reacted with scepticism.
"We saw the reports of the press conference that the deputy prime minister gave. Frankly, we didn't see anything terribly new there," State Department spokeswoman Victoria Nuland said.
"We still believe that the faster Assad goes, the more chance there is to quickly move on to the day after."
The West has long demanded Assad's departure, accusing him of butchering his own people during a 17-month conflict that began as a peaceful uprising but has deteriorated into a brutal fight between regime forces and armed rebels.
Syria's traditional allies Russia and China have blocked UN resolutions on the conflict, rejecting what they see as foreign attempts at regime change, leaving the international community deeply divided over how to end the conflict.
Activists say more than 23,000 people have been killed since March 2011, while the UN puts the death toll at 17,000 and says hundreds of thousands more have fled or been made homeless in a major humanitarian crisis.
Obama had put Assad's regime on notice Monday that although he had not ordered military action "at this point," Washington would regard any recourse by Damascus to its deadly arsenal as crossing a "red line."
"There would be enormous consequences if we start seeing movement on the chemical weapons front or the use of chemical weapons," he told reporters.
Syria admitted in July that it has chemical weapons and could use them in case of any "external aggression" but not against its own people.
Jamil brushed off Obama's comments as "simply propaganda" linked to the November presidential election while Russian Foreign Minister Sergei Lavrov said: "There should be no interference from the outside."
"The only thing that foreign players should do is create conditions for the start of dialogue," Lavrov said, but also told Jamil that efforts by Damascus to end the conflict were "not enough."
Jamil is also trying to seal a deal for fuel supplies and other urgent Russian assistance and loans for Syria, whose economy has been crippled by the conflict, but said he had failed to secure a final pledge from Moscow.
The comment appears to betray a growing impatience by Russia to achieve some sort of progress toward peace talks in the face of the escalating violence and little sign of concessions from Assad.
The Syrian Observatory said 198 people were killed on Tuesday, including dozens who were summarily executed or slain in an attack on a funeral procession by troops who raided the Damascus suburb of Maadamiyat al-Sham.
It is impossible to verify the claims.
Heavy shelling was reported across many parts of Aleppo on Tuesday, including an area where a Japanese reporter was killed Monday, becoming the fourth foreign journalist killed in the conflict.
At least 31 civilians, including five women and five children, were killed there on Tuesday alone, the Observatory said.
A top FSA commander, Colonel Abdel Jabbar al-Okaidi, said the rebels now controlled 60 percent of the now battered manufacturing hub that was largely spared the conflict until fierce fighting erupted there a month ago.
"The people are with us," he said. "How else do you think we could have lasted a month?
But a security source in Damascus dismissed the claims as "completely false", saying the army was making slow progress in what the regime has warned would be a "mother of all battles" to retake the city.
"Reinforcements from both sides are heading to Aleppo. It is a war that will last a long time," he said.
The relentless fighting has triggered a mass refugee exodus and left another 2.5 million in need of aid inside the country, creating what US State Department officials said was one of the worst crises in the world today.
The conflict spilled over again into neighbouring Lebanon, with six dead in clashes that first erupted late Monday between pro- and anti-Damascus regime supporters in the northern port city of Tripoli, security officials said.