However, it landed in a drain and did not explode and the youth was apprehended by the Army.
"A team of Army apprehended a person involved in grenade lobbing at an election rally in Nohama area of Noorabad today," an army official said.
"The apprehended person will be handed over to the police after the rally is over," the official said adding a bomb disposal squad has been rushed to the spot to destroy the explosive.
The polling in the constituency will be held in the second phase on December 2.