At least 340 people were killed and scores injured when a supermarket in the Paraguayan capital Asuncion caught fire causing one floor to collapse.

The fire broke out on Sunday afternoon at the Ycua Bolanos supermarket during its peak shopping hours.

Hundreds of rescue workers and bystanders tried helping out the trapped people inside. Smoke hung in the air for hours afterward and some flames could still be seen flickering after nightfall.

Paraguay's Channel 9 reported that 340 bodies had been  recovered, citing rescue workers and police accounts. The government had no official toll of deaths and injuries hours after the fire erupted.

Officials were still trying to determine the cause of the fire.

Witnesses said they heard an explosion before the fire swept through the building, causing the ground floor of the store to collapse into the basement parking garage, said district police commander Aristide Cabral.

Some burned bodies could be seen seated upright in cars  in a first-floor parking lot, blackened in the intense heat.

Public Health Minister Julio Cesar Velazquez told reporters, "I have never seen a disaster like this. The firefighters were taking out, as best as they could, the bodies, the injured and people suffering from smoke  inhalation. It's horrible."

Agencies