Militants in Pakistan ambushed security forces overnight in response to an unexpected prior attack on an aid convoy in the nation’s troubled northwest, resulting in a shootout that left four troops dead, officials said on Tuesday.

The ambush took place just hours after authorities had sent reinforcements to address Monday’s attack on an aid truck convoy in Kurram, a district in the volatile Khyber Pakhtunkhwa province, where a driver and a security official were killed.

Officials reported that some security forces were injured in an overnight ambush in Kurram, where recent clashes between rival Shiite and Sunni tribes have resulted in at least 130 deaths. Authorities also stated that several trucks travelling to Parachinar, the central city in Kurram, were looted and set on fire.

Dr Qaiser Abbas, a physician at a hospital in Parachinar, stated that on Monday night, they received the bodies of four security personnel from Kurram. Authorities mentioned that a large-scale operation is planned to capture those responsible for the attacks.

Shiite Muslims form the majority in certain parts of Kurram, but they are a minority in Pakistan, where Sunnis make up the majority. The region has experienced sectarian violence in the past, with militant Sunni groups targeting the Shiite minority.

None of the group has claimed responsibility for the attack. Still, suspicion is expected to fall on ethnic Baloch separatists, whom the government has previously blamed for similar attacks on passenger buses in Balochistan.

Last year, the Baloch Liberation Army carried out three separate attacks on vehicles in Balochistan, killing dozens. The region has long been a hotspot for insurgency in Pakistan, with various separatist groups primarily targeting security forces.

None of the group has yet claimed accountability for the latest attacks, but it is suspected that Sunni militants may be responsible.

The separatists are calling for independence from Islamabad's central government.

On Tuesday, the military reported that troops had killed 30 militants the previous day during an operation in South Waziristan but did not provide further details.

These operations target the Pakistani Taliban, known as Tehrik-e-Taliban Pakistan (TTP), who are allied with the Afghan Taliban, the group that took power in Afghanistan in 2022.