QUETTA - At least four people were injured in a hand grenade attack in Quetta, on Sunday while rockets were fired in Kohlu during a company search for oil and gas in Barkhan.According to police, unknown people hurled a hand grenade at hotel located at Imdad Chowk adjacent to Jinnah Road that exploded with a huge bang and injured four people.Police and other law-enforcement agencies rushed to the site soon after the blast and moved the injured to nearby Civil Hospital for medical aid. The injured were identified as Muhammad Hashiq, Adil, Naseer and Arif.Windowpanes of several shops were also shattered due to the blast. Police tightened security and started a search in the City to round up the accused.Meanwhile, armed men fired several rockets from mountains targeting a camp of workers of a company in Kohlu who were busy in searching for oil and gas.  The rockets landed in deserted areas and exploded, however, no loss of life and damage to property occurred. Law-enforcement agencies started a search in the area to arrest the attackers.