Syrian troops and army defectors have fought one of the biggest battles in Syria's nine-month uprising while a protest strike shut businesses in a new gesture of civil disobedience, residents and activists said.
Arab foreign ministers will meet on Saturday to discuss a response to Syria's conditional acceptance of an Arab peace plan aimed at ending its crackdown on pro-democracy protesters, Egypt's MENA news agency said, citing an Arab diplomat.
And in a major international development likely to raise Western pressure on Syrian President Bashar Al-Assad, France's Foreign Minister Alain Juppe said Paris believed Syria was behind attacks that wounded French peacekeepers in neighbouring Lebanon on Friday.
In Sunday's fighting, Syrian troops mainly from the 12th Armoured Brigade based in Isra, 40 km (25 miles) from the southern border with Jordan, stormed the nearby town of Busra Al-Harir.
A housewife in Busra, who did not want to be named, told Reuters by telephone that the town was being hit by machinegun fire from tanks. Her children were crying.
The sound of explosions and heavy machineguns was heard there and in Lujah, an area of rocky hills north of the town, where defectors from the army have been hiding and attacking military supply lines, residents and activists said.
"Lujah has been the safest area for defectors to hide because it is difficult for tanks and infantry to infiltrate. The region has caves and secret passageways and extends all the way to Damascus countryside," said an activist, who gave his name as Abu Omar.
Syria has barred most independent journalists, making it difficult to gauge the extent of participation in the strike. Official state media made no mention of it.
"For the first time we have seen business close in multiple districts in Damascus and spread to most of the suburbs and provinces. The aim is to reach civil disobedience that encompasses all sectors and forces the regime down," said Rima Fleihan, a member of the opposition Syrian National Council.
"The cost will be more human lives but I am afraid it is less costly than an armed uprising and the regime dragging the country into a Libya-type scenario, she said.
Assad has been widely condemned abroad for what Western and Arab countries describe as a crackdown on peaceful protests. His government says it is defending Syria from a foreign-backed insurgency by armed militants.
The United Nations says more than 4,000 Syrians have been killed since March. Assad says the number of dead is far lower and most of them have been from the state security forces.
The official news agency SANA said 13 soldiers killed by "armed terrorist groups" were buried on Sunday.
In Cairo, Egypt's MENA news agency said Arab foreign ministers would meet on Saturday to discuss a response to Syria's conditional acceptance of an Arab peace plan.
Syria faces sanctions from Arab nations in response to its violent crackdown on protests against President Assad.
The Arab League repeatedly has extended deadlines for Syria to agree to a plan that would see Arab monitors oversee its withdrawal of troops from towns. The latest expired on 4 December.
MENA said that a small group of ministers would meet first on Saturday, followed by a broader meeting of ministers led by Qatar from the 22-member League the same day. Syria has been suspended from the League.
Syrian Foreign Minister Walid al-Moualem wrote to the League saying Damascus was prepared to sign an ageement that would allow League monitors into Syria, on certain conditions.
France strongly condemned the attack in southern Lebanon, where a roadside bomb wounded five French peacekeepers. It was the third such incident this year involving United Nations forces deployed near the frontier with Israel.
"We have strong reason to believe these attacks came from there (Syria)," French Foreign Minister Alain Juppe said on RFI radio. "We think it's most probable, but I don't have proof."
When asked if he believed Hezbollah had carried out the attack on behalf of Damascus, Juppe said: "Absolutely. It is Syria's armed wing (in Lebanon)."
There was no immediate response from the Syrian authorities or from Hezbollah, which had condemned the attack.
France has been leading Western efforts to force Assad to end the crackdown. Juppe has suggested a need to set up zones to protect civilians, the first proposal by a major Western power for outside intervention on the ground.