Tsunami warnings to the local population of quake-hit Sulawesi island failed on the "last mile", causing many to be surprised by waves as high as six metres, according to a German research centre that developed a warning system used by Indonesia.
"We don't know how many victims could be buried there, it's estimated hundreds", said Sutopo Purwo Nugroho, spokesman for the National Disaster Mitigation Agency.
Another villager, 52-year-old Idrus, who uses one name, said that "up to Saturday we still saw many people screaming for help from the roofs".
The European Union said it released an initial 1.5 million euros (1.7 million dollars) in emergency humanitarian assistance, while the United States said it stood "ready to assist in the relief effort". "We need field hospitals, medical workers, medicines and blankets". One video posted on YouTube showed people grabbing boxes of supplies from a truck.
The magnitude 7.5 quake struck at dusk Friday and spawned a tsunami said to have been as high as 6 meters (20 feet) in places.
As they waited for aid Sunday, survivors took matters into their own hands, entering shops and wheeling away trolleys filled with food and water.
A search and rescue team had reached Donggala but were uncontactable as electricity and communications were still cut off in the region, Sutopo said.
A family transports a coffin carrying a lost relative (background) as people loot a convenience store (foreground) in Palu, in Indonesia's Central Sulawesi province, on September 30, 2018.
Indonesia's Metro TV on Sunday broadcast aerial footage from a coastal community in Donggala, close to the epicentre of the quake.
Almost 2,500 houses in the Balaroa and Patobo complexes were buried under mud following the quake and the six-metre-high tsunami wave, complicating the rescue process, Sutopo said.
Indonesia, which sits on the seismically active Pacific Ring of Fire, is all too familiar with deadly earthquakes and tsunamis.
Utami said most of the 343 prisoners in Donggala had been jailed for corruption and drugs offenses.
For two days, Edi Setiwan helped pull the dead and the living out of a sea of mud and debris, all of them victims of one of Indonesia's deadliest earthquakes and tsunami in years.
Government officials said some 1,200 inmates fled at least three prisons in the region.
For health and religious reasons, 300 bodies, which have been identified, will be initially buried.
Local military spokesman Mohammad Thorir said the area near a public cemetery could hold 1,000 bodies.
But many people are still looking for missing loved ones.
Indonesian authorities are reporting that the death toll from Saturday's natural disaster and resulting tsunami is continuing to climb, as rescue workers sift through floodwaters and debris.
Internal Affairs Minister Tjahjo Kumolo, asked about reports of looting on social media, said he had ordered authorities to help people get food and drink and businesses would be compensated.
People suffering from a lack of food and supplies were also becoming more desperate.
Palu is at the head of a bay, about 10 km long and 2 km wide, which had "amplified" the wave as it was funnelled towards the city, a geophysics agency official said.
Military aircraft were sent to bring people out of Palu, where crowds of people clutching bags and boxes were waiting at the airport.
There were several commercial flights operating in Palu, including ones run by Lion Air, Sriwijaya, Garuda Indonesia and Wings Air, with around 22 round-trip schedules, Budi said.