The nature of the explosion is being ascertainedAt 20 people were injured in an explosion at a bank in Punjab's Sadiqabad on Thursday. The bank was located off the National Highway. According to rescue officials, everyone injured in the explosion were pedestrians and have been shifted to Sadiqabad's Tehsil Hospital. Four are in critical condition and have been shifted to the Sheikh Xayed Hospital.Police and rescue teams have completed their rescue operation. They were earlier searching beneath the debris for victims.Related: Fire at Karachi's Karim Centre doused after an hourOfficials say they have yet to determine the cause of the explosion.The bank building completely collapsed in the explosion. Two nearby shops were damaged. Six bikes, two cars and a bus have been also been damaged by the blast.Follow SAMAA English on Facebook, Twitter, and Instagram.