Security guards prevented a suicide bomber from killing Pakistan's interior minister in an attack at a political gathering in a northwestern town Saturday that left at least 22 dead and 35 wounded, officials said. Interior Minister Aftab Khan Sherpao sustained minor injuries, police said. Footage broadcast on state television showed the minister walking to his car after the blast, with bloodstains on his face and white shalwar kameez tunic. There was no immediate claim of responsibility for the bombing, but suspicion will fall on Islamic militants who have repeatedly targeted top Pakistani officials, including President Gen. Pervez Musharraf, for support of the US-led war on terror. The suicide bomber struck soon after Sherpao had finished addressing a public gathering of his political party in an open field in the northwestern town of Charsadda. Security guards blocked the attacker as he tried to get close to Sherpao, an intelligence official said. The attacker detonated the bomb moments later. Salim Jan, 22, who suffered minor injuries, said Sherpao was meeting with people after the speech when the bomb exploded. Jan described the carnage of the aftermath. "I saw the head of a man there. I saw bodies there. I also saw security men helping Sherpao to go toward his car," he said. Mohammed Khan, a police official, said the minister was in stable condition and was shifted to a hospital in the city of Peshawar, which lies about 30 kilometers (18 miles) to the south. Asif Iqbal Daudzai, spokesman for the government of North West Frontier Province, said the attack killed 22 people and wounded more than 35. The dead included two staff members and two security guards of Sherpao. Khan said at least 10 of the wounded were in critical condition. The son of Sherpao, Sikandar Khan Sherpao, and some lawmakers and security officials were among the injured, he said. The intelligence official, who spoke on the condition of anonymity because of the sensitive nature of his job, said investigators had found the head of the suicide bomber. He had no details on the attacker's identity. The bombing comes a day after an apparent missile strike killed four people in the border region of North Waziristan, considered a stronghold of Taliban and al-Qaida militants. The US military and NATO in neighboring Afghanistan denied any involvement. It wasn't clear if Pakistani security forces played any role. The government claimed - despite witness accounts to the contrary - that the dead and wounded were making bombs and had accidentally caused an explosion.