Five Pakistani soldiers were killed on Friday when a bomb detonated as their vehicle passed through the restive northwestern region bordering Afghanistan, the military said.

The latest attack was carried out in Kurram district of the mountainous Khyber Pakhtunkhwa province, which has long been a hive of Islamist militant groups including the Pakistani Taliban and the local chapter of the Islamic State group.

"An improvised explosive device exploded on a vehicle of Security Forces," the military said in a statement.

"Five brave sons of the soil... made the ultimate sacrifice and embraced Shahadat (martyrdom)," the statement added.

No group immediately claimed responsibility for Friday's attack.

The Pakistani Taliban -- known as Tehreek-e-Taliban Pakistan (TTP) -- is the most active militant group in the area and regularly targets security forces.

Attacks have spiked in Pakistan since the Taliban returned to power in neighbouring Afghanistan in August 2021.

In a similar attack earlier this month, seven soldiers were killed in the Lakki Marwat district of the same province.

Islamabad accuses Kabul's new rulers of failing to root out militants sheltering on Afghan soil as they prepare to stage attacks on Pakistan. The Afghan Taliban government denies the accusations.