All victims were members of the same family, Tolo News reported.
The family was driving past the centre in Pul-e-Khumri city when the IED detonated shortly after 12 noon, health officials said.
Earlier in the day, a suicide bomber blew himself up among a crowd lining up to get access to an election-related registration site in Kabul, killing 31 people and injuring 54, officials said.
The blast occurred at around 10 a.m. in front of a school located in Kabul's Qala-e-Nazir area, Xinhua news agency reported.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
