"It's all chaos here. I myself have seen four dead, two of them are children. I have seen four wounded women."
Tensions between Pakistan's majority Sunni Muslims and Shias have made the road unsafe for minorities travelling to the nearby Kurram tribal region.
Police recently had declared it safe, but Shias are provided security to travel through it.
More than 4,000 people have died in sectarian violence between the country's Sunni majority and Shia minority since the late 1980s.