A Pakistani official says a roadside bomb has exploded near a team of bomb disposal experts, killing three soldiers.

Government administrator Kamran Afridi said Sunday's blast took place as the soldiers were clearing a road in Ghulam Khan, in the North Waziristan tribal region, ahead of a security convoy.

No one immediately claimed responsibility for the attack.

North Waziristan, which borders Afghanistan, was a longtime stronghold of al-Qaida and other insurgent groups. Pakistan says army operations in recent years have largely driven out the militants, but the area still sees regular attacks.