Pakistani police were on Saturday questioning a group of people from an Islamic seminary that were detained following a suicide bombing that killed more than 50 people at a mosque in the volatile North-West Frontier Province, according to dpa. The target of the attack, former interior minister Aftab Sherpao, was unhurt, but more than 100 people were injured while offering prayers Friday morning for the Muslim Eid al-Adha holiday at his ancestral home and political base of Sherpao. Pakistan has seen a huge spike in suicide attacks aimed at the government and military in recent months, and US officials have said al-Qaeda has re-established itself in the tribal belt along the border with Afghanistan. "Local police have detained four to five people from a madrassa in Sherpao village where the carnage was carried out, including three Afghan migrants," said Feroze Khan, the senior superintendent of police in the province's Charsadda district, which includes Sherpao village. "They are not formal suspects; we are only questioning them," he said, declining to explain why police were tipped off to the religious school. Mohammed Sharif Virk, inspector general of police in the North- West Frontier Province, said the official tally from the blast, one of the biggest suicide attacks in Pakistan in recent years, was 48 dead and 114 injured. Other officials have said the death toll was more than 50. "According to our estimate, 7 to 8 kilograms of explosive materials were packed in a suicide jacket along with ball bearings, for maximum affect," he said. The blast was so powerful and the damage was so much that most of the evidences are lost," "We suspect Islamic militants in the tribal areas who we believe also carried out the last attack on Mr Sherpao."