Ten Syrian security personnel were killed on Friday in a roadside bomb planted by "terrorists" in Sahm al Golan village in the southwest of the country near the border with Israel, state television said.
It said that the bomb weighed 100 kilograms but gave no other details.
France, meanwhile, seeking to avoid civil war, is drafting a new resolution for the United Nations Security Council designed to allow a larger observer force to be deployed in Syria with up to 500 observers as well as helicopters, French Foreign Minister Alain Juppe said on Friday.
The UN Security Council - divided between Western countries that want to topple Syrian President Bashar Assad, and Russia and China which support him - is supposed to endorse a proposal to send a larger observer force as part of a six-point UN-Arab League plan for a political transition in Syria.
"This is our last chance to avoid civil war," Juppe told BFM television. "We have this (Kofi Annan) agreement with all our partners so we have to give it a chance for a few more days. We have to give the Annan mission every chance to succeed, including with a strong force of 500 observers."
Juppe's remarks came as a spokesman for Annan, the UN-Arab League's special envoy, said that the full advance team of 30 ceasefire monitors should be deployed in Syria in the coming week and that preparations were under way for up to 300 observers to be dispatched there.
The week-old ceasefire is "very fragile" and the situation on the ground is "not good," with incidents and casualties reported every day, Annan's spokesman Ahmad Fawzi said.
UN Secretary-General Ban Ki-moon has suggested that the 15-nation Security Council quickly pass a resolution authorizing the "initial deployment" of up to 300 unarmed monitors.
On Thursday, US Secretary of State Hillary Clinton stepped up the pressure on Damascus, saying the UN Security Council should consider adopting a sanctions resolution that is capable of being enforced if Syria does not permit an adequate monitoring mission.
The French government of President Nicolas Sarkozy, who faces the first round of a tough re-election battle on Sunday, has long led calls for Assad to step aside. It has also said it would support military action if there was a UN mandate, something that remains unlikely given Moscow and Beijing's opposition to intervention.
"If in a few days or weeks it doesn't work then we will go to a next phase and a new resolution that has sanctions and intervention, as Mrs. Clinton indicated," Juppe said.
Clinton said a resolution proposing sanctions would probably be vetoed now, but that world powers should push for a Chapter 7 sanctions resolution, including travel, financial sanctions, an arms embargo, and ultimately military intervention.
French Socialist presidential frontrunner Francois Hollande said on Friday he would send troops to Syria in the event of a UN mandate for military intervention.
"If it (military intervention) is done in the framework of the UN, then we will take part in this intervention," Hollande, who is comfortably ahead of Sarkozy for a May 6 poll runoff, told Europe 1 radio.
Friday is the last day that candidates can campaign before Sunday's first-round election, in which four new polls show Hollande to be gaining over the president.
"The thing about Hollande is he is always playing catch-up. It's very easy to say we will support a military intervention if there is a resolution, but the problem is knowing whether that is possible," Juppe said of Hollande's remarks.
Hollande, who was an adviser to the last Socialist government in France that took the decision to intervene in Afghanistan in 2001, has similar foreign policy objectives to incumbent Sarkozy. However, Hollande has faced criticism after announcing plans to withdraw troops from Afghanistan at the end of 2012, a year earlier than scheduled.