KARACHI: President Asif Ali Zardari’s chief security officer, Bilal Sheikh was among three people killed in a blast targeting a double cabin vehicle in the Gurumandir area of the city on Wednesday.

Sheikh was traveling in his bullet-proof vehicle that was ahead of his police security squad. Reports indicate that at least 12 people have been injured in the blast. Four of the injured are said to be in critical condition.

SSP CID Raja Umer Khitab said the blast was a suicide attack. Khitab further said that the attacker had followed Sheikh's vehicle and detonated his explosive vest when the car stopped near a street side fruit vendor.

According to initial reports the bomb was packed with ball bearings and contained 3-4 kilograms of explosives.

The president has condemned the killing of Sheikh and the two other individuals. Assefa Bhutto Zardari tweeted: RIP Bilal Sheikh Chief Security Officer to Bilawal House. He worked personally with my father and siblings to ensure our safety.