"The Hara area, which recently fell to rebel forces, was hit by air strikes and surface-to-surface missiles, causing 18 deaths, including four children," said the Syrian Observatory for Human Rights.
Hara stands less than two kilometres (one mile) from a strategic hill in Daraa province that Al-Nusra Front jihadist rebels seized on October 5 in a battle which cost the lives of 30 regime forces and 29 insurgents.
More than 180,000 people have been killed in Syria since an uprising against President Bashar al-Assad's regime began in 2011, escalating into a multi-sided civil war that has drawn thousands of jihadists from overseas.