Three women, a six-year-old girl and a nine-year-old boy were among the dead.

PESHAWAR (AFP) - The death toll from a roadside bomb targeting a passenger vehicle in Pakistan’s northwest rose to 13 on Wednesday as three critically injured people died overnight in hospital, officials said.

The incident, which occurred in the Godar area of Kurram tribal district early Tuesday, has been claimed by both the Jamaat-ul-Ahrar (JuA), faction of the Pakistani Taliban and the Islamic State group (IS).

Three women, a six-year-old girl and a nine-year-old boy were among the dead, Baseer Khan, a top government official in Kurram tribal district told AFP -- adding that the passengers were targeted because they belonged to the Shiite religious minority.

JuA pledged alleigance to IS in 2014, but a year later said it had re-joined the Tehreek-e-Taliban (which in turn is allied to Al-Qaeda, a foe of IS).

Since 2016, JuA and IS have both laid claim to several attacks, notably a suicide bombing at a civil hospital in southwest Quetta last year that killed 73 people -- raising the possibility they are colluding, or that JuA, which has footsoldiers on the ground, is allowing IS to also take credit in order to achieve propaganda goals.