The attack appeared to target Aftab Sherpao, who served as interior minister in the outgoing government of Pakistani President Pervez Musharraf. According to the BBC, the bombing took place at a mosque within Sherpao's residential compound near the city of Peshwar, a relatively secure location 80 miles northwest of the country's capital.
"We feel that Sherpao was the target. There are so many mosques in that area. Why did the bomber select that mosque for the attack?" Reuters quoted Federal Secretary of the Interior Syed Kamal Shah as saying.
Witnesses told the BBC that several of Sherpao's bodyguards were among those killed in the attack, but the politician, who is running in next month's parliamentary elections, was unhurt.
Correspondents on the scene at the hospital in Peshawar described the facility as chaotic with injured arriving in pickup trucks, ambulances rushing to and from the scene of the bombing and the wounding crying for help.
Authorities were investigating how a suicide attacker could penetrate Sherpao's compound, where some 1200 worshippers had gathered. According to the head of security, all those who entered had been made to pass through a body scanner and were searched with metal and explosive detectors.
National officials were quick to defend their efforts to prevent such an attack, with Hamid Nawaz, the current interior minister, maintaining there was no security lapse.
"All possible care had been taken, there was no lapse as such ... but such an incident can happen at such a gathering," Nawaz said on Aaj TV.
The Associated Press reported the bomb contained between 13-17 pounds of explosives and was filled with nails and ball bearings to maximize casualties.
According to witnesses, the explosion took place in the middle of prayers marking Eid al-Adha, the holy holiday marking the end of the month of Ramadan.
"It's inhuman. No Muslim can do such a thing on the day of Eid," Mohammad Asad, who lost his two cousins in the attack, told Reuters.
In a telephone interview with The New York Times, Sherpao said that the bomb exploded two or three rows behind him as he and his family prayed in the front row of the mosque.
"It was a massacre," Sherpao told the Times. "I can tell you that."
In April, Sherpao was slightly wounded when a suicide bomber attacked a rally for his political party in the nearby town of Charsadda, killing at least 28 people.
