Syrian state media and opposition activists say a mortar shell has hit an election rally for President Bashar Assad, killing a number of people, according to the Associated Press.

Assad was not at the rally, which the state-run SANA news agency said happened Thursday, May 22 night in the southern city of Daraa. SANA said a number of people were killed.

The Britain-based Syrian Observatory for Human Rights also reported Thursday's attack. It said Friday that the mortar shell killed 21 people, including 11 civilians. It said the shell wounded more than 30 people.

The Observatory relies on reports from a network of activists on the ground.

Assad is widely expected to win a third, seven-year mandate at the June 3 presidential election.