A roadside bombing targeted a minivan in Pakistan's northwestern tribal region on Tuesday, killing nine people, a local government official and the military said.

The blast ripped through the van as it was travelling through a minority Shiite region of the Kurram tribal area, which borders Afghanistan, said Arif Khan, a tribal administration official in the town of Parachinar. The area has long been the scene of sectarian violence.

A woman and two children were among the nine killed, Khan said. The explosion also wounded 13 people. With few adequate medical facilities in the area, a Pakistani army helicopter evacuated the wounded to a nearby military hospital.

No group immediately claimed responsibility for the attack. Pakistani Taliban and other Sunni militant groups often target minority Shiites whom they consider to be heretics. The Islamic State group has also claimed several recent attacks in the country.

For over a decade, Pakistan has been fighting Islamic militants who have killed tens of thousands of people. Islamabad has also undertaken several large-scale offensives in the tribal regions in an effort to rout militants from the area.

Also on Tuesday, Pakistani paramilitary forces raided an apartment in the port city of Karachi, acting on a tip that militants were hiding there, police officer Aurangzeb Khattak said.

The paramilitary force said that after a seven-hour siege, three militants, including a woman, blew themselves up inside the apartment. The explosion also killed a 5-year-old child. A fourth militant was killed trying to flee the scene.

Karachi has long been home to political, ethnic and militant violence.