QUETTA, July 14: Quetta was rocked by four explosions on Thursday night. A hand-grenade was hurled at the building of the office of the director-general health services. After five minutes, another grenade targeted the office of excise department on Sariab Road, smashing windowpanes . The third targeted the head office of the Post Master General Balochistan in the same area. The location of fourth explosion could not be immediately ascertained.—Staff Correspondent