A two-storey under-construction plaza near Multan's Bosan Road collapsed on Tuesday leaving at least one dead and four others injured, according to police.
Recovered bodies were shifted to Nishtar Hospital.
More casualties are feared as, according to initial reports, at least 20 people, motorcycles and rickshaws are trapped beneath the rubble of the collapsed building.
Nearby buildings have also been affected by the collapse.
Rescue sources say it is unclear how many people are trapped. A police official speaking to DawnNews estimated that around 20-22 people were buried under the debris.
"We were alerted of the incident around 4pm. The route leading to the plaza is clear for rescuers but all other traffic has been diverted."
"There were four structures beneath the building and there were around 20-22 people in them," he said, adding that four people were recovered alive and one body was recovered.
An eyewitness told DawnNews that the building was a two-storey plaza in which a partition was being installed, which may possibly have triggered the collapse.
Rescuers face a race against time as they struggle to conclude the operation before nightfall.
An emergency has been imposed in hospitals in the area and rescue operations supervised by the DCO Multan are ongoing.
Heavy machinery and a contingent of over 400 police officials are aiding in the rescue operation, police said.
The operation is being hindered due to severe traffic jams. Traffic is being diverted from the site of the collapse.