The bomb went off soon after chief minister of Khyber Pakhtunkhwa province, Amir Haider Hoti, and other ministers in his provincial cabinet had left the meeting in the town of Nowshera.
According to police, a remote-controlled bomb that was fixed in a motorcycle hit the ANP rally venue after the public address concluded.
As a result of blast, five persons were killed while 15 others were injured including four policemen. The injured were shifted to District Headquarter Hospital where five are said to be in critical condition.
Approximately three kg of explosives were used in the blast, police said.
Rescue work has kicked off while the area has been cordoned off.