DERA ISMAIL KHAN: Unidentified terrorists attacked the Police Lines in Dera Ismail Khan with a grenade on Friday, official sources said. "The grenade was lobbed with the help of a launcher from around 300 to 400 metres distance," said a source. The source added that the grenade landed near a washroom. A wall and the washroom were damaged in the attack. However, no casualty was reported. The police cordoned off the area after the attack and launched a search operation.