One person died and three were injured when a fire broke out on a bus in a heavily fortified army compound in Damascus early on Wednesday, Syrian state news agency SANA reported.
One source at the site of the explosion suggested an electrical fault had set the petrol tank on fire, the agency reported.
The explosion happened in the bus while it was near the entrance of a heavily fortified Republican Guards housing compound in the west of the Syrian capital, SANA said.
Another source with knowledge of the matter, who asked not to be named, said at least five military personnel were killed and 11 other personnel were wounded in the blast.
Blasts in Damascus have been rare since forces loyal to President Bashar al-Assad took control of rebel enclaves around the city.
Ten years into Syria’s conflict, President Bashar al-Assad has survived the insurgency which started with peaceful protests in March 2011.
He now holds sway over most of the country, helped by Russia’s military presence.
There have been several attacks this year on army vehicles in eastern Syria by suspected Islamic State militants who still operate in the sprawling desert area.