At least 20 people were killed and scores of others injured in a suicide bombing at a public meeting attended by Pakistani Interior Minister Aftab Ahmed Khan Sherpao on Saturday, officials said.

The bomb exploded at 4 p.m. local time (1100 GMT) at Station Korona near Charsadda, some 135 km west of Pakistani capital Islamabad and located in North West Frontier Province.

A suicide bomber blew himself up when Sherpao finished his speech and was heading to his car, the private News Network International (NNI) news agency reported.

Inspector General Police of North West Frontier Province (NWFP) Muhammad Sharif Virk confirmed 20 deaths in the blast, while NNI quoted hospital sources as saying that at least 22 people died and some 60 others were injured.

Chief Minister of NWFP Akram Khan Durrani said that several policemen were among those killed.

Earlier reports said Sherpao and his son were hurt in the attack, which was denied by the Interior Ministry.

Sherpao and his son returned home safe and sound, private Geo News channel reported.

Pakistani President Pervez Musharraf and Prime Minister Shaukat Aziz condemned the blast and told the NWFP government to immediately apprehend the mastermind of the blast.

Local reports quoted sources as saying that Sherpao was targeted and that he had been on the "hit-list" of the terrorists.