Twin explosions set off by a pair of suicide bombers shook a southern Syrian city on Saturday, killing and wounding dozens of regime forces, an activist group said.

The Britain-based Syrian Observatory for Human Rights said the early morning blasts in Daraa targeted an encampment for government troops in the city. The Observatory said the explosions were followed by clashes between regime forces and rebels fighting to topple President Bashar Assad.

The state-run news agency SANA said the blasts caused multiple casualties and heavy material damage, but did not provide further details.

The southern city of Daraa was the birthplace of the uprising against Assad, which erupted in March 2011. The conflict began largely with peaceful protests against Assad’s rule but turned bloody after rebels took up arms in response to the regime’s crackdown.

“I heard two very loud explosions and a third smaller one followed by bursts of gunfire,” said Mohammad Abu Houran, an activist in Daraa. He said the first two were likely car bombs and the third a mortar shell or rocket propelled grenade.

Abu Houran said black smoke could be seen over the high-security area, which was sealed off. Heavy shooting could be heard from the area for about 10 minutes after the explosions, he added.

The Daraa explosions come a day after as many as 11,000 people were said to have fled Syria over just 24 hours, to escape fierce fighting between rebels and government forces the latest surge of refugees fleeing the civil war.

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