Islamic State says it is behind a series of deadly blasts in Syria which have killed more than 200 people.

The militant group said "soldiers of the caliphate" carried out surprise attacks on government and security centres in the largely government-held southern city of Sweida on Wednesday.

They were among the worst attacks in recent months.

The Britain-based Syrian Observatory for Human Rights said three suicide attackers set off booby-trapped belts in Sweida city, as other blasts hit villages to the north and east.

A fourth suicide explosion hit the city later.


The attacks included a suicide bombing at a busy vegetable market.

The carnage sparked clashes later in the day between Syrian troops and allied militias and IS militants.

Image: The death toll includes 62 civilians

"IS fighters stormed villages in the province's northeast and killed residents in their homes," the head of the observatory Rami Abdel Rahman said.

Mr Rahman said it was the bloodiest death toll in Sweida province since the start of the war in 2011 - and one of the deadliest ever in Syria.

The monitoring group put the toll at more than 200 - including 89 civilians and 94 local militiamen.

It said dozens of IS militants were also killed in the clashes.

IS has been largely defeated in Syria and Iraq, but still has pockets of territory in eastern and southern Syria.

Since its offensive started in June, President Bashar al Assad's forces have retaken territories controlled by the rebels along the Golan Heights frontier and are now fighting militants in the country's southern tip.