The IED was planted on the roadside in village Naina-Batpora and detonated by militants when the private car of PDP worker Ghulam Mohiuddin was passing through the area, a police spokesman said.
He said the vehicle, however, safely passed through the area minutes before the explosion.
Although, Mohiuddin was not present in the vehicle at the time of the explosion, his three personal security officers escaped unhurt, the spokesman said.
He said a massive hunt has been launched to nab the militants involved in the incident.