Bahawalpur police described the man, whose name was not reported, as "deranged," and arrested him Tuesday, The Express Tribune reported Wednesday.
Shortly after the incident, the crowd of 1,500 to 2,000 people gathered outside the Chanighot police station, burning police vehicles and demanding officers hand over the alleged blasphemer, the newspaper reported.
Officer Ghulam Mohiuddin Gujjar said nine police officers were injured in the incident, during which they tried to fend off the mob using tear gas.
Once the mob took custody of the man, they doused him in gasoline and set him afire, The Express Tribune reported.
Police said they are investigating the incident and reinforcement was sent to Bahawalpur to bring the area under control.