Islamabad, Mar 16 (Reporter) A policeman was killed and five others were injured in an explosion targeting a police vehicle in Quetta, the capital city of Pakistan's southwestern Balochistan province, on Saturday night, officials said. The incident took place at around 9:00 p.m. local time (1600 GMT) when an anti-terrorism force mobile unit was passing through the area, sources from Quetta police told Xinhua on condition of anonymity. "Preliminary investigations suggest that the explosion was caused by a roadside-fitted remote-controlled improvised explosive device, though a conclusive statement about the nature of the blast is awaited yet," the sources added. The injured policemen were shifted to a nearby hospital for medical treatment, and security forces have cordoned off the area while an investigation is underway. No group has claimed the attack yet...////...