The official SANA news agency said the explosion occurred outside the headquarters of the national railroad and was blamed on terrorists.
Seven of the eight people killed were part of a work crew conducting maintenance on the al-Hijaz Railway headquarters. The injured at Damascus Hospital included a number of women and children, SANA said.
The blast occurred about the same time a bombing at a traffic roundabout in Sweida was reported by a provincial police source. SANA said another eight victims died and 41 were hurt.
The Syrian government said Wednesday it would attend the so-called Geneva II negotiations without pre-conditions as a means of finding a way to end the violence, CNN said.
Bouthaina Shaaban, an adviser to Syrian President Bashar al-Assad, told Russia Today TV it was prepared to sit down with international representatives and a delegation from the opposition rebels, whom she dismissed as being a front for Saudi Arabia's intelligence agencies and representing the interests of al-Qaida and other terrorist groups.