The first explosion was followed by another in which a journalist died and two police officers were injured, local authorities were reported as saying.
He further revealed that the second attacker was among reporters who had gathered at the scene to cover the attack.
No individual or terrorist group have claimed responsibility for the incident so far.
Last week, 52 people were killed and more than 100 others were injured when a suicide bomber blew himself up that hit a crowd waiting at a voter and ID registration centre in Kabul.
The Islamic State (IS) terrorist group claimed responsibility for the attack.