The country flag is flying half-mast in all government institutions in Southern Sindh province of Pakistan Monday to mourn the killing of more than forty innocent victims in a blast in the provincial capital Karachi Sunday night.  At least 40 people were killed and over 140 were injured in a blast that ripped through the densely populated Abbas Colony of Karachi city. The town was populated mainly by the Shia community.  The blast was so severe that it set residential flats and an adjacent commercial area on fire. It left a four-foot deep and ten-foot wide crater.  Earlier, police said that it was a remote-controlled Improvised Explosive Device (IED) explosion but, later, it said that at least 150 kilograms of explosive were used and initial findings suggest that a four-wheeler was used as the carrier of the bomb.  A religious party \"Majlis e Wahdit e Muslimeen (MWM)\" representing Shia sect has called for three days of mourning. They have termed it a targeted attack on the Shia community. Many other Shia organizations are also observing strike to record their protest. The MWM has demanded the ultimate arrest of the culprits of the blast.  Meanwhile, the Governor Sindh has directed the Commissioner to supervise the relief activities. He announced that the Government will rebuild all the damaged flats and shops.  Also, Sindh Chief Minister Syed Qaim Ali Shah has constituted a six-member committee, headed by CID Additional IG, to probe the incident.  The Goods Transport Association has declared that truckers will not hit the roads today. The Business community is also observing a shutter down strike.