At least six people were killed and more than 30, including women and children, were injured when a powerful bomb exploded near a passenger bus on the main Quetta-Mastung highway on Monday. Levies sources said a Noshki-bound passenger bus coming from Quetta with about 60 people onboard was targeted with a bomb planted along the road in the Darengrra area of Mastung. As a result, six people were killed on the spot while more than 30 were injured. Locals and Levies Force officials rushed to the spot and helped move the injured to Civil Hospital Mastung. Doctors said the condition of several of the injured was serious and the death toll could rise. Those seriously injured were shifted to Bolan Medical Complex Quetta, where three people were said to be critical. Security forces cordoned off the area after the blast and launched a search operation, however, no arrest could be made.