In Pakistan, in a fresh spate of violence that erupted in Karachi on Saturday – one day ahead of by-polls – has left at least 15 people killed and over four dozens others injured while unknown armed men forced shops in different areas to close.Meanwhile, five vehicles including an OB van of a private television channel have been reportedly torched in different areas during the violence-ravaged incidents.The violence spread in several parts of the city after unidentified attackers opened fire and injured a man of Orangi Town where by-election is being held on Sunday.