A suicide attacker detonated a bomb packed with ball bearings and nails amid hundreds of holiday worshippers on Friday at the home of Pakistan's former interior minister, killing at least 50 people, authorities said.

It was the second suicide attack in eight months apparently targeting Aftab Khan Sherpao, who escaped injury. One of his sons was wounded.

Suspicion will likely focus on the pro-Taliban or al-Qaida militants active in the northwestern region of the country where the attack occurred.