PESHAWAR, Pakistan (AP) — Gunmen opened fire on passenger vehicles carrying Shiite Muslims in restive northwest Pakistan on Thursday, killing at least eight people and wounding others, police said.

The attack happened in Kurram, a district in the northwestern Khyber Pakhtunkhwa province where clashes between majority Sunni Muslims and minority Shiites have killed dozens of people in recent months.

No one has claimed responsibility but Kurram has been a scene of sectarian violence in recent months, and the latest violence came a week after authorities reopened a key highway in the region after keeping it closed for weeks following deadly clashes.

Local police official Nusrat Hussain said several vehicles carrying passengers were traveling in a convoy from the city of Parachinar to Peshawar, the capital of Khyber Pakhtunkhwa, when gunmen opened fire.

He said at least five passengers were in a critical condition at a hospital.

Shiite Muslims make up about 15 percent of the 240 million population of Sunni-majority Pakistan, which has a history of sectarian animosity between the two communities.