Dawn News quoted police officials as saying that riots erupted after the postmortem report of the seven-year-old girl confirmed that she was raped before being murdered.
Two people died of gunshot injury when the protesters "armed with sticks and stones attempted to storm the deputy commissioner's office and clashed with police", it said, adding that two others sustained bullet injuries.
The Punjab administration said that six personnel, including four policemen and two civil defence personnel, were arrested for allegedly opening fire at the mob.
Zainab, 7, was abducted on January 4 when she had gone to a religious centre in Road Kot area.
Later, her body was recovered from a heap of trash near the Shahbaz Khan Road.
Her parents, who were in Saudi Arabia to perform Umrah, arrived here yesterday and laid her body to rest in a graveyard. (ANI)