Pakistani police and intelligence officials are working to identify a suicide bomber who killed at least 28 people and wounded 52 others, including the interior minister.
A senior police investigator said on Sunday the bomber appeared to be a man in his 30s, possible from Afghanistan or from Pakistan's tribal areas bordering Afghanistan.
The bomber blew himself up moments after Interior Minister Aftab Ahmed Khan Sherpao finished speaking at a rally Saturday in the town of Charsada. The town is in Pakistan's North West Frontier Province, bordering Afghanistan.
The minister escaped with minor injuries, but at least one of his aides and several of his guards were killed.
Afghan President Hamid Karzai and Pakistani President Pervez Musharraf are to hold talks in Turkey this week on terrorism and other security concerns.