Unidentified terrorists carried out a late-night hand grenade attack on the house of an official of Frontier Constabulary in the Mathra area here. According to police, there was no casualty in the attack, however the house was partially damaged. The police said that the FC official Fazl Rabi was receiving messages from militants of the banned outfit TTP, Afghanistan for payment of ransom of Rs 30 million. The police force reached the site soon after the incident and started a search operation.