Pakistani intelligence officials say a roadside bomb attack on an army convoy in North Waziristan tribal region has killed four soldiers and wounded four others.

Two intelligence officials said the bomb planted in Haider Khel area alongside the main Bannu-Miran Shah Road exploded Sunday when a military convoy was passing, while a civilian curfew was in force.

Both officials spoke on condition of anonymity because they are not authorized to speak to reporters.

North Waziristan is a sanctuary for Islamic militants who often carry out attacks against security forces. Two recent attacks on military checkpoints killed 21 soldiers and three civilians. The Pakistani military usually retaliates for such attacks with small-scale operations but has shown reluctance to launch a full-fledged military offensive.