Rebel forces ambushed an army vehicle in northern Syria on Tuesday, killing three soldiers and capturing two others, Syrian human rights observers said.
Syria's northern neighbour Turkey said it feared there could be an exodus of Syrians if the violence got worse, and that border states might have to create a buffer zone. Russia in contrast warned major powers against interference.
Syrian President Bashar al-Assad faces mounting economic sanctions over what a UN report said on Monday was systematic murder, torture and rape ordered from the top.
But he shows no sign of buckling under pressure to end his crackdown on protesters or in the face of armed rebellion by military deserters.
"The security forces vehicle was targeted while driving in the city of Saraqeb in Idlib province by a group of suspected army defectors," the Syrian Observatory for Human Rights said in a statement.
Government forces later killed a civilian and wounded three others in raids in Saraqeb, it said. In a district of Homs city, an 8-year-old girl was shot dead at a checkpoint.
Two civilians died of their wounds in the area of Rinkous outside Damascus on Tuesday and a 33-year-old man was killed by sniper fire as he tried to escape arrest, it said.
The Observatory said families in the area had been unable to bury seven people killed there since Sunday.
The United Nations report on Monday accused Syria of crimes against humanity in the 8-month-old repression of a revolt in which the UN says at least 3,500 have been killed.
The United States, the European Union and the Arab League have stacked up a range of economic sanctions against Damascus while ruling out military intervention.
Syria, diplomats say, is not like Libya, where Nato air power paved the way for a successful revolution against the Gaddafi dictatorship. It is more ethnically diverse and has far more people. Assad still has strategic allies and strong support at home and the rebels hold no territory.
Turkey said it must prepare for "any scenario".
"If tens, hundreds of thousands of people start advancing towards the Iraq, Lebanon, Turkey borders, not only Turkey but the international community may be required to take some steps such as a buffer zone," Turkish Foreign Minister Ahmet Davutoglu said in a television interview.
"We don't want that to happen but we must consider and work on that scenario," he said.
France has raised the idea of a secured humanitarian corridor, a step which would appear to imply some use of armed forces for security and logistics, if camps were set up on Syria's border to accommodate masses of refugees.
"If the oppression continues, Turkey is ready for any scenario. We hope that a military intervention will never be necessary," Davutoglu said. "The Syrian regime has to find a way of making peace with its own people."