The goods convoy was travelling with an armed escort to Parachinar, a town in Kurram district that borders Afghanistan, which has been racked by violence between Sunni and Shi’ite Muslims for decades.

Around 250 people have been killed in a fresh flare-up of fighting since July, according to local officials.

The gunmen opened fire on security forces protecting the aid convoy, killing one truck driver and wounding seven others.

A paramilitary reinforcement unit was also ambushed and five soldiers killed.

“The attackers also torched three (border force) vehicles,” a police officer told AFP on the condition of anonymity.

“A total of 15 people, including a female bystander, were injured, while six people, including five (border force) personnel, lost their lives,” he said.

The official said helicopter gunships targeted hideouts in the mountains after the attack.

The local government of northwestern Khyber Pakhtunkhwa province and tribal leaders have announced numerous truces that have failed to last and key roads in and out of the district have been shut down in an attempt to quell the violence.

The most recent peace deal was announced on Jan 1 but an aid convoy en route to the area was attacked just days later, wounding several local officials and members of their security escort.

A “high-level” meeting, chaired by the chief minister in the provincial capital, Peshawar, ordered another operation in Lower Kurram, where clashes and ambushes occur frequently.

The feud between Sunnis and Shi’ites stems from decades-old tensions over farmland.

Members of the Shi’ite community are particularly vulnerable because they must pass through Sunni-majority neighbourhoods to reach essential services.