One person died and at least three were injured when a military bus exploded in a heavily fortified compound in Damascus on Wednesday.
The explosion occurred near the entrance of a Republican Guards housing compound in the west of the Syrian capital, state news agency Sana reported.
A source at the site of the explosion said an electrical fault set the petrol tank on fire, the agency reported.
Blasts in Damascus are rare since forces loyal to President Bashar Al Assad took control of rebel enclaves around the city.
There have been several attacks this year on army vehicles in eastern Syria by suspected ISIS militants, who still operate in the sprawling desert area.
Syria in recent days has suffered an escalation of mortar attacks on its army checkpoints in the southern province of Deraa in the biggest flare-up of violence since government forces retook the region three years ago.
Relations between locals and government officials are severely strained and there are sporadic protests and simmering anger.
Jordan closed the Jaber crossing in Syria's southern Deraa province in response, days after Jordanian and Syrian officials discussed ways to stop banditry and extortion hampering trade in the south of Syria.