A bomb exploded near a highway at the southern edge of Syria's capital Damascus on Sunday morning, state media reported.
An attacker was arrested and no one was injured, state news agency SANA said.
The head of the city's civil defence, Asef Hababe, told Reuters that military technicians had detonated a device.
The Syrian Observatory for Human Rights, a UK-based war monitoring group, said the explosion was near a security post.
Syria's war has killed hundreds of thousands of people, forced more than half its pre-war population from their homes and dragged in global powers.