A MORTAR shell struck a large tent in southern Syria where supporters of President Bashar Assad had gathered for election campaigning on Thursday night.

The attack killed at least 21 people and wounded scores more.

There was no immediate claim of responsibility for the attack in Daraa. Rebels trying to overthrow President Assad frequently fire mortar shells into Syria’s major cities, including the capital Damascus, from opposition-held suburbs.

But the overnight attack on an election function underscored concerns that rebels will step up attacks against government strongholds in the run-up to the June 3 poll to disrupt an election that they fear they cannot win.

Ahmad Masalma, an opposition activist in Daraa, claimed that rebels from the Free Syrian Army had repeatedly warned civilians to stay away before firing a mortar shell at the tent in a government-held area. He said there were about 100 people in the tent, including members of pro-Assad militias, officers and employees. 

More than 25 people were killed and the rest were wounded in the attack, which “set the tent ablaze and sent shrapnel flying everywhere,” he said.

The rebel spokesman said the mood had been celebratory at the tents, which were festooned with posters of Mr Assad and Syrian flags.

“They had loud music and dabka (traditional dance.)

“It was very provocative and an insult to the blood of martyrs.”

President Assad is widely expected to win a third seven-year mandate.