By Fathin Ungku and Kanupriya Kapoor
PALU, Indonesia (Reuters) - Indonesian President Joko Widodo ordered more rescuers to hunt for victims of a devastating earthquake and tsunami on the island of Sulawesi, saying on Tuesday everyone had to be found, as the scale of destruction became clearer.
Some remote areas have been out of contact for more than three days and officials fear the confirmed death toll of 844 could soar into the thousands when losses in those areas are revealed.
"The are some main priorities that we must tackle and the first is to evacuate, find and save victims who've not yet been found," Widodo told a government meeting to coordinate disaster recovery efforts.
He said he had ordered the national search and rescue agency to send more police and soldiers into the affected districts, some cut off since Friday's 7.5 magnitude quake and subsequent tsunami waves destroyed roads, triggered landslides and downed bridges.
The Red Cross said the situation was "nightmarish" and reports from its workers venturing into one cut-off area, Donggala, a region of 300,000 people north of Palu and close to the epicentre, indicated it had been hit "extremely hard".
Four badly hit districts have a combined population of about 1.4 million.
Most of the confirmed dead have been in the small city of Palu, 1,500 km (930 miles) northeast of Jakarta.
The quake triggered tsunami waves as high as six metres (20 feet) that smashed into the city's beachfront, while hotels and shopping malls collapsed in ruins and some neighbourhoods were swallowed up by ground liquefaction.
Among those killed in the area were 34 children at a Christian bible study camp, a Red Cross official said.
More than 50 of the dead were taken to a mass grave on the outskirts of Palu on Tuesday, while rescuers held out hope they could still save lives.
"We suspect there are still some survivors trapped inside," the head of one rescue team, Agus Haryono, told Reuters at the collapsed seven-storey Hotel Roa Roa.
About 50 people were believed to have been caught inside the hotel when it was brought down. About 12 people have been recovered from the ruins, with one more body on Tuesday.
Three of the victims were recovered alive.
Haryono pored over the hotel's blueprints and building plans, searching for possible pockets and a way through to them. A faint smell of decomposition hung in the air.
"We have to be very careful so we don't risk hurting any survivors when we move the debris," he said.
Power has yet to be restored in the area and access by land to outlying villages has been disrupted by broken roads, landslides and downed bridges.
Nearly 60,000 people have been displaced and are in need of emergency help, while thousands have been streaming out of stricken areas.
Indonesia has said it would accept offers of international aid, having shunned outside help earlier this year when an earthquake struck the island of Lombok.
Aftershocks have rattled jangled nerves.
A particular horror in several areas in and around Palu was liquefaction, which happens when soil shaken by an earthquake behaves like a liquid. [nL4N1WI06W]
About 1,700 houses in one neighbourhood were swallowed up, with hundreds of people believed buried, the national disaster agency said.
Before-and-after satellite pictures show a largely built-up neighbourhood just south of Palu's airport seemingly wiped clean of all signs of life by liquefaction.
Elsewhere on the outskirts of Palu, lorries brought 54 bodies to a mass grave dug in sandy soil.
Most of the bodies had not been claimed, a policeman said, but some relatives turned up to pay respects to loved ones at the 50 metre (165 feet) trench, where the smell of decomposition was overpowering.
"It's OK if he's buried in the mass grave, it's better to have him buried fast," said Rosmawati Binti Yahya, 52, whose husband was among those placed in the grave, before heading off to look for her missing daughter.
Commercial airlines have struggled to restore operations at Palu's quake-damaged airport but military aircraft took some survivors out on Monday, while about 3,000 people thronged the airport hoping for any flight out.
A navy vessel capable of taking 1,000 people at a time was due to be deployed to help with the evacuation.
The power company was working to restore electricity while the state oil firm had sent in fuel, officials said.
Teams of police were out on the streets on Tuesday, clearing debris and providing some reassurance to traumatised residents worried about looting.
Sulawesi is one of the archipelago nation's five main islands.
For Sulawesi map, click https://tmsnrt.rs/2OYa4YD
For graphic on Catastrophe in Sulawesi, click https://tmsnrt.rs/2OqQlUo
(Writing by Robert Birsel; Editing by Lincoln Feast and Paul Tait)