A car bomb exploded in Homs on Tuesday morning, Syrian state television said, two days after the city went back under full government control for the first time since 2011.
Authorities destroyed another vehicle rigged with explosives near a Shi'ite Muslim shrine south of Damascus, the broadcaster and other state media reported.
Islamic State claimed responsibility for both attacks via its online media outlet Amaq.
Syrian state television, quoting the head of the Homs health authority, said the blast killed four people and injured 32 in the al-Zahraa neighborhood, which lies around 160 km (100 miles) north of the capital.
Homs governor Talal al-Barazi told Syrian state news the attack came in response to recent gains that Syrian government forces had made in Homs.
On Sunday, hundreds of Syrian rebels and their families left Homs's last opposition-held district, al-Waer, which has been under siege by the army and allied forces for more than a year.
The evacuation completed a deal that brought Homs back under the control of President Bashar al-Assad's government for the first time since the start of the conflict.
The Syrian Observatory for Human Rights, a Britain-based war monitoring group, said the explosion in the al-Zahraa neighborhood killed five people.
Pictures broadcast on state television showed a burned vehicle chassis in a blast site in a street, with damage to buildings and surrounding cars.
The second blast occurred near the Sayeda Zeinab shrine, close to a checkpoint on the Damascus airport road, where Syrian authorities intercepted the car and blew it up. State media said the vehicle contained two people when it was destroyed
