At least three people were killed including the chief security guard of President in southern Pakistani city Karachi on Wednesday. The chief security officer of the president, Bilal Sheikh was an active member of the ruling Pakistan People\'s Party in Sindh province. A spokesman for the Bilawal House, the residence of President Zardari in Karachi, confirmed Sheikh\'s death. According to initial reports by police, chief security officer was among three people killed in a blast targeting a double cabin vehicle in the Gurumandir area of the city. At least 12 people have been injured in the blast while four of the injured are said to be in critical condition. A senior police official, Sheikh was traveling in his bullet-proof vehicle that was ahead of his police security squad. The President, Asif Ali Zardari has condemned the killing of Sheikh and the two other individuals in strong words. The security officials reached the site of the blast and an investigation was started. The injured people were shifted to the nearby hospital where an emergency was imposed.