The twin blasts happened near a hospital in the central Syrian city of Homs.
ISIS bomber parked car and detonated 150kg of explosives near hospital.He then set off his suicide belt as scores of people gathered at the scene.
Another 54 were wounded, some seriously, in the attack in the Al-Zahraa neighbourhood and were being treated at hospitals throughout the city.
The vehicle used in the attack was carrying at least 150kg of explosives, said Governor Talal Barazi.
In its statement, ISIS named the bomber as Abu Ahmed al-Homsi and said he parked the car and detonated it before then activating his explosives belt.
ISIS said the toll from the attack was more than 25 dead, with 70 wounded.
Firefighters, security forces and dozens of other men packed into the residential street where the blast occurred, searching for victims and seeking to rescue the injured.
The Syrian Observatory for Human Rights also said 16 people were killed and dozens wounded, adding that some were in critical condition.
E/S1