The attack could raise pressure on Islamabad to wage an offensive in North Waziristan, which has largely escaped Pakistani army action in recent years despite US pressure for a crackdown. Militant attacks on troops in the region have also been rare.

The army statement said the attack Thursday occurred in the Datta Khel area of North Waziristan, and that the convoy was "carrying out a routine movement" to the area from the town of Miran Shah. Sixteen soldiers were wounded in the ambush, one of the worst known to have occurred against the army in the border region in several months.

The statement did not give many details. However, two intelligence officials in the northwest said tribesmen joined local Taleban fighters to stage the ambush after a 15-year-old boy in the area was allegedly shot to death by an earlier group of traveling soldiers.

The boy was killed when troops opened fire after a roadside bomb exploded near the convoy, the officials said on condition on anonymity because they were not authorized to speak to media on the record.

Pakistan has carried out several army operations in its semiautonomous tribal belt, where Al-Qaeda and various Taleban factions have long thrived. The offensives have mainly been aimed at militant groups targeting Pakistani institutions.

North Waziristan has largely escaped the operations because most of the militant networks there — unlike groups such as the Pakistani Taleban — are focused on the war in Afghanistan.

The US wants Pakistan to take on the North Waziristan networks, but Islamabad says it does not have the resources to open another front.

The area struck Thursday is controlled by Sadiq Noor, one of the few Pakistani Taleban commanders known to operate in the region, said two other intelligence officials, also asking that their names not be used.

It's unclear whether the attack will have any impact on the Pakistan's army future designs in North Waziristan.