Officials said the remote-controlled bomb exploded in Sepoy in Lower Orakzai near a van that was carrying civilians, Geo News reported.
Two women, an 11-year-old boy and a 3-year-old girl were among the dead, officials said. Four other people were wounded.
Geo News said an investigation had begun but did not report anyone had claimed responsibility.
Swim Week Miami Beach 2014 [PHOTOS]