Heavy clashes broke out before dawn on Sunday between the Syrian army and deserters, leaving 11 of its soldiers dead, human rights activists said.
Another 20 soldiers were wounded in the fighting in Daraa province, south of the capital, while nine soldiers defected to join the rebel troops, the Syrian Observatory for Human Rights said.
In addition to the deadly clashes in the village of Basr al-Harir, the Britain-based watchdog also reported heavy machinegun exchanges between the army and deserters in the Daraa town of Dael. There was no immediate word on any casualties.
Cradle of the protests against President Bashar al-Assad that erupted in March, Daraa has been one of the provinces hardest hit by the deadly crackdown unleashed by his regime.
The latest deaths came as Arab League foreign ministers prepared to meet in Cairo to review the record of a widely criticised observer mission to Syria, in the face of growing calls for the bloc to cede to the United Nations the lead role in trying to end the bloodshed.