Rescuers in Indonesia have pulled a 38-year-old man out alive from beneath a collapsed building three days after an earthquake and tsunami devastated the city of Palu.
Indonesian TV stations showed video from the National Search and Rescue Agency of its workers freeing Sapri Nusin from the rubble of a destroyed finance building on Monday.
He was conscious and talking to his rescuers as they worked by flashlight.
After freeing him, rescuers put him on a stretcher and carried him away.
There was no immediate word on his condition.
At least 844 people have been confirmed dead since a 7.5 magnitude earthquake struck on Friday, followed by a tsunami with waves as high as six metres.
That number is expected to rise as search teams continue their work and reach more remote areas on the island of Sulawesi.
Nearly 50,000 people have been displaced by the disaster.
Earlier some 100 Indonesian troops left the city of Makassar in southern Sulawesi island, more than 700km from Palu, to help with rescue efforts in the devastated areas.
The troops boarded a naval ship on Monday morning and headed to Palu and Donggala.
They were expected to join some 1300 personnel already on site, including military and police, and were bringing food, water and other supplies.
Dozens of people were reported trapped in the rubble of several hotels and a mall in Palu, with hundreds more feared buried in landslides that engulfed villages.
President Joko Widodo told reporters getting them out was a priority.
"The evacuation is not finished yet, there are many places where the evacuation couldn't be done because of the absence of heavy equipment but last night equipment started to arrive," Widodo said.
"We'll send as much food supplies as possible today with Hercules planes, directly from Jakarta," he said, referring to C-130 military transport aircraft.
Indonesia's disaster agency said later more heavy equipment and personnel were needed to recover bodies.
A mass burial of victims has begun, with Local Army Commander Tiopan Aritonang saying on Monday that 545 bodies would be brought from one hospital alone.
A 10m by 100m grave was being dug in Palu.
One woman was recovered alive from ruins overnight in the Palu neighbourhood of Balaroa, where about 1700 houses were swallowed up when the earthquake caused soil to liquefy, the national rescue agency said.
Indonesian rescuers searching for survivors at a collapsed house at Balaroa district in Palu, central Sulawesi, Indonesia. Source: AAP
"We don't know how many victims could be buried there, it's estimated hundreds," said Sutopo Purwo Nugroho from the National Disaster Mitigation Agency.
All but 23 of the confirmed deaths were in Palu, a city of about 380,000 people, however nearly three days on from the earthquake and tsunami the extent of the disaster was not known.
Authorities are bracing for the toll to possibly climb into the thousands as connections with remote areas up and down the coast are restored.
The government has allocated 560 billion rupiah ($A52 m) for the recovery.
