Multiple attacks killed at least 38 people and wounded 37 others in Sweida and villages northeast of the Syrian city, the head of the health authority told state-run Ikhbariyah TV.
A suicide bomber blew himself up near a marketplace in the city early on Wednesday, as Islamic State militants mounted attacks on several villages to the northeast.
State media said authorities were hunting down militants in the city.
Want stories like this in your inbox?
Sign up to exclusive daily email
More Stories from Middle East