At least 22 people have been killed after Syrian rebels shelled a campaign rally in support of President Bashar al-Assad.
The shells hit a tent where supporters of Mr Assad had gathered in the southern city of Daraa last night.
At least 30 people were wounded, the Syrian Observatory for Human Rights said.
Eleven civilians, including a child, were among those killed in the attack, which occurred in the al-Matar district.
Mr Assad is running for re-election on 3 June.
He faces two little known challengers in the vote and is widely expected to clinch a third seven-year term in office despite the country's civil war.
More than 160,000 people have been killed in the three-year-old conflict, according to the Observatory, which monitors violence on both sides through a network of sources in the country.
Millions more have fled their homes.