The death toll from a powerful earthquake on Indonesia’s Sulawesi island has jumped to 56, authorities said on Sunday, with thousands left homeless as rescuers raced to find anyone still alive under mountains of rubble.

More than 820 people were injured and about 15,000 left their homes after the 6.2-magnitude quake struck in the early hours of Friday, according to the disaster mitigation agency (BNPB). Some of the panicked residents sought refuge in the mountains, while others went to cramped evacuation centres.

Rescuers have spent days hauling corpses from beneath crumpled buildings in Mamuju, a city of 110,000 people in West Sulawesi province, where a hospital was flattened and a shopping mall lay in ruins.

Others were killed south of the city.

Aerial images from the devastated seaside city showed buildings reduced to a tangled mass of twisted metal and chunks of concrete, including the regional governor’s office.

Authorities have not given a figure for how many survivors have been rescued.

A pair of young sisters plucked from under the mass of concrete and other debris were treated in hospital.

Meanwhile, corpses were recovered from under a collapsed hospital, while five members of a family of eight were found dead in the crumpled remains of their home.

The thousands left homeless by the earthquake took to makeshift shelters – many little more than tarpaulin-covered tents filled with whole families -that were lashed by heavy monsoon downpours.

They said they were running low on food, blankets and other aid, as emergency supplies were rushed to the hard-hit region.

Many survivors are unable to return to their destroyed homes, or were too scared to go back fearing a tsunami sparked by aftershocks, which are common after strong earthquakes.

“It’s better to take shelter before something worse happens,” said Mamuju resident Abdul Wahab, who took refuge in a tent with his wife and four children, including a baby.

“We hope the government can deliver aid soon like food, medicine and milk for the children,” he added.

The earthquake’s epicentre was 36km (22 miles) south of Mamuju and it had a relatively shallow depth of 18km (11 miles).

Straddling the so-called “Pacific Ring of Fire”, Indonesia is regularly hit by earthquakes. In 2018, a devastating 7.5-magnitude quake and subsequent tsunami struck the city of Palu, in Sulawesi, killing thousands.

Just two weeks into the new year, the world’s fourth-most populous country is again battling several disasters.

Floods in North Sulawesi and South Kalimantan province each have killed at least five this month, while landslides in West Java province have killed at least 28, authorities said.

On January 9, a Sriwijaya Air jet crashed into the Java Sea with 62 onboard.

East Java’s Semeru mountain erupted late on Saturday, but there have been no reports of casualties or evacuations.(Al Jazeera)