In Wednesday's attacks, worst bloodshed in Sweida since civil war began in 2011, more than half the people killed were civilians.
Beirut: The death toll in coordinated Islamic State group suicide bombings and shootings in southern Syria rose to nearly 250 overnight, more than half of them civilians, a monitor said on July 26.
Wednesday's attacks hit Sweida, a Druze-majority province mostly held by the government which had remained relatively insulated from the country's seven-year civil war.
The death toll climbed steadily throughout the day and into the night, the Syrian Observatory for Human Rights, a Britain-based monitoring group, said.
"The toll is now 246 people dead, including 135 civilians," said Observatory chief Rami Abdel Rahman.
The others killed were pro-government fighters or residents who had taken up arms to defend their villages.
"The toll keeps rising as civilians who were wounded are dying and people who were unaccounted for are found dead," Abdel Rahman told AFP.
The onslaught began with a triple suicide bombing in the city of Sweida, which was followed by attacks with guns and explosives on villages to its north and east. A fourth blast hit the provincial capital later in the day.
IS claimed the assault hours later.
At least 45 jihadists died carrying it out, the Observatory said. It was the worst bloodshed to hit Sweida province since the civil war began in 2011.
Syrian state media reported deadly attacks on Sweida and surrounding villages but did not give a specific toll.