Improvised explosive device went off near passenger vehicle in Upper Dir district, says police official

At least four people were killed and six others wounded on Sunday in a bomb blast in northwest Pakistan, an official said.   
"The IED [improvised explosive device] went off near a passenger vehicle on a main road in Sheringal area of Upper Dir district," Mian Naseeb Jan, a local police officer, told media on phone.
The vehicle was completely destroyed and all injured persons have been transported to a nearby hospital, Jan said.
After the explosion, police cordoned off the area and launched a search operation.
No group has claimed responsibility for the attack, but the outlawed Tehreek-i-Taliban Pakistan has claimed responsibility for previous attacks on security forces and civilians in the region.