At least 13 people have been killed and 51 others injured as a blast ripped through Urdu Bazaar Lahore on Tuesday evening at a time when a large number of people were gathered to observe Chehlum of Hazrat Imam Hussain (R.A) and Urs of Hazrat Data Ganj Bakhsh (R.A). According to sources, policemen are also among the dead while the injured were being shifted to different hospitals of city. Rescue teams reached the spot and started relief activities. Police cordoned off the area and asked the people to vacate the area to avoid any other untoward incident.