Syrian rights activists say government security forces have clashed with army defectors in several parts of the country, as Syrians voted in municipal elections that are the first test of reforms promised by the government.
The London-based Syrian Observatory for Human Rights said the fighting Monday was taking place in the northwestern Idlib province and in the southern province of Daraa.
The elections cover more than 17,000 seats on local councils across the country's 14 provinces. The government has called for a large voter turnout.
The poll comes a day after violence killed up to 18 people nationwide. The clashes Sunday included a major confrontation in southern Syria, where army defectors battled loyalist forces backed by tanks near the Jordanian border.
The Syrian Observatory for Human Rights said eight people were killed across Syria Sunday, while the opposition Local Coordination Committee put the death toll at 18. It was not possible to independently verify the death toll.
Also Monday, Syria denied any involvement in an attack Friday that wounded four French peacekeepers in southern Lebanon. The statement by Syria's foreign ministry followed accusations from French Foreign Minister Alain Juppe, who said Sunday that Syria was probably behind the attack, though he had no evidence.
In the flash point city of Homs, an opposition leader said the government has warned protesters to hand in weapons and surrender defecting military members by Monday night or face bombardment.
CNN quoted Lieutenant Colonel Mohamed Hamdo of the Free Syrian Army as saying the 72-hour warning was given Saturday.
Several regions across Syria observed the opposition's call for a general strike Sunday, the first working day of the week, as activists push for an end to President Bashar al-Assad's government through civil disobedience.
The opposition Local Coordination Committee has urged citizens to gradually escalate the protests by holding sit-ins, closing facilities and refusing to work in the public sector.
Also Sunday, fallout from the anti-government protests spilled over into neighboring Jordan, where a crowd of angry Syrian citizens attacked their country's embassy. The Syrian mission in Amman has been the scene of several protests since the anti-government uprising broke out in Syria nine months ago.
Mr. Assad has been facing mounting international pressure to end a crackdown on dissent that the United Nations says has claimed more than 4,000 lives.