وزير الداخلية السوري: الحادث ناجم عن انفجار اطار الحافلة ما أدى الى سقوط ثلاثة قتلى
As Syrian officials said, the explosion was due to a wheel explosion

.
A wheel blew up and killed 3, in addition to a dozen of injuries, in addition to a a certain damage in the surrounding buildings..
What a damn wheel !!