PANAJI: A five-story building under construction in southern India collapsed on Saturday, killing at least seven workers and leaving dozens more feared trapped under the rubble, police said.

Authorities were trying to determine how many people were on site when the structure crumpled in Canacona, about 70 kilometers (44 miles) from the state capital of Panaji, Police Superintendent Shekhar Prabhudessai said. Witnesses said about 40 workers were on site.

''It was like an earthquake when the building fell,'' witness Ramesh Naik said. ''You could not see what exactly had happened because of the dust.''

Police and residents pulled seven bodies from the wreckage, while firefighters and rescue workers were sifting through the debris for survivors.

Ambulances took at least three seriously injured workers to a hospital for treatment.

Prabhudessai said the cause of the collapse had not been determined.

Building collapses are common in India, as massive demand for housing and lax regulations often encourage builders to cut corners by using substandard materials or add unauthorised extra floors.