Hundreds of army defectors in southern Syria have fought with loyalist forces in one of the biggest armed confrontations in the nine-month uprising, and a strike shut businesses in a new gesture of civil disobedience, residents and activists said.
In another development likely to raise international pressure on President Bashar al-Assad, French Foreign Minister
Alain Juppe said on Sunday that Paris believed Syria was behind attacks that wounded French peacekeepers in neighbouring Lebanon on Friday.
Syrians are casting ballots in local elections on Monday, but turnout is expected to be low as activists have called for a boycott of the polls.
The SANA state news agency showed pictures of people voting and reported that voters "flocked" to the polls.
Almost 43,000 candidates are standing for 17,588 seats in the country's 1,337 administrative units.
Earlier on Sunday, troops from the 12th Armoured Brigade, based in Isra, 40km from the border with Jordan, stormed the nearby town of Busra al-Harir, the Reuters news agency reported.
Al Jazeera's Nisreen El-Shamayleh, reporting from near the Jordan-Syria border, said that the clash started when "tens of tanks mounted with machine guns opened fire in that area earlier on Sunday morning to try to put an end to a general strike" called for by the opposition.
The sound of explosions and heavy machine guns was heard in Busra al-Harir and in Lujah, an area of rocky hills north of the town, where defectors have been hiding and attacking military supply lines.
At least 26 people were killed by government troops on Sunday, including a woman and four children, activists said. Nine of them were killed in the city of Homs, six in Hama, three in Deraa, two in Idlib and another two outside of Damascus.
At least five Syrian soldiers, including a military officer, were also reportedly killed.
Opposition activists said they had shut down much of the capital and other towns with a strike, the biggest walkout by
workers since the protest movement demanding Assad's removal erupted in March.
The Local Co-ordination Committees (LCC), a Syrian rights group, organised the civil disobedience campaign, including the closure of shops and universities in protest, as well as sit-in demonstrations across the country.
"This strike is really a desperate action, a desperate cry from the Syrian people, the last civilian action we could do," Ashraf al-Moqdad, a member of the Syrian opposition calling for civil disobedience, told Al Jazeera.
"We've been demonstrating peacefully for nine months. Thousands of us have been murdered by Assad and his thugs. We've been waiting for real concrete action from the international community ... What else can we do?
In-depth coverage of escalating violence across Syria
"This is part of our desperate action to get the attention of the international community to look at us. Please look at our situation. We are desperate now."
Security forces in Syria told striking shopkeepers on Sunday to open up their stores or they would be smashed.
"We heard reports that troops burned down at least 178 stores and shops in Deraa to try and take revenge against civillians who have shut down their stores and shops and are basically observing this general strike," our correspondent said.
Syria has barred most independent journalists from the country, making it difficult to gauge the extent of participation in the strike.
A witness who toured Damascus said most shops were closed in the main shopping street of the old Medan quarter in the centre of the capital where there has been a heavy security presence. The main souq in Old Damascus remained open.
Central parts of the capital and the business hub Aleppo seemed calm, though there are reports of strikes taking hold in some areas on the outskirts of both cities.
"There is nothing going on," said Rula, a schoolteacher in Damascus. "Nothing seems out of the ordinary."
The opposition used Facebook and online videos to call for an open-ended "Strike for Dignity" to begin on Sunday.
The LCC has termed the strike "the first step in an overall civil disobedience" campaign to overthrow the government.
Navi Pillay, the UN human rights commissioner, has said that "more than 4,000 people" have been killed in the government crackdown on dissent in Syria since protests broke out in March.