A bomb explosion has rocked a town in Pakistan's southwestern Balochistan province, leaving at least two people killed and 12 others injured. The bomb went off at a residential building in a bypass road in Chaman town of Balochistan on Thursday, a Press TV correspondent reported, quoting local officials. Pakistani security forces cordoned off the area after the blast and transferred the injured to a local hospital. Meanwhile, unknown gunmen killed at least eight people and injured 21 others in separate incidents in the southern port city of Karachi on Wednesday. The gunmen torched several vehicles, including two trucks in various locations in Karachi. They also set tires on fire and blocked roads in different areas. In another incident, unidentified armed men destroyed two police vehicles and a link bridge in the outskirts of Peshawar in northwestern Khyber Pakhtunkhwa province of Pakistan later on Wednesday. Militant attacks in Pakistan are on the rise as pro-Taliban elements in the country have vowed to avenge the death of former al-Qaeda leader Osama bin Laden, who the US claims to have killed in an unauthorized military operation in Pakistan in early May.