A mortar shell has struck a tent in southern Syria where supporters of President Bashar al-Assad had gathered for election campaigning, killing at least 21 people, opposition activists said.
According to the Britain-based Syrian Observatory for Human Rights, Thursday’s attack also wounded at least 30 people.
There was no immediate claim of responsibility for the attack in Daraa.
The overnight attack underscored concerns that rebels will step up attacks against government strongholds in the run-up to the June 3 presidential election to disrupt the voting.
Ahmad Masalma, an opposition activist in Daraa, told the AP news agency that rebels from the Free Syrian Army umbrella group fired a mortar shell at the tent in a government-held area, after repeatedly warning civilians to stay away. He said there were about 100 people in the tent.
Masalma said the mood was celebratory at the tents, festooned with posters of Assad and Syrian flags.
Assad was last seen in public on April 20 when Syrian state television broadcast images of him visiting the ancient Christian village of Maaloula, north of Damascus, after government forces recently recaptured it.