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A mass burial of earthquake and tsunami victims began in Indonesia Monday as the death toll climbed to 844 and the need for equipment to dig for survivors grew increasingly desperate.

The toll is largely from the city of Palu and is expected to rise as areas cut off by the damage are reached. The magnitude 7.5 earthquake struck at dusk Friday and spawned a tsunami said to have been as high as 20 feet in places.

Local Army Commander Tiopan Aritonang said that 545 bodies would be brought from one hospital alone. The grave being dug in Palu will be 33 feet by 330 feet and can be enlarged if needed, said Willem Rampangilei, chief of Indonesia's National Disaster Mitigation Agency.

"This must be done as soon as possible for health and religious reasons," he said. Indonesia is majority Muslim, and religious custom calls for burials soon after death, typically within one day.

Local military spokesman Mohammad Thorir said the area adjacent to a public cemetery can hold 1,000 bodies.

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All of the victims, coming from local hospitals, have been photographed to help families locate where their relatives were buried. Video footage showed residents walking from body bag to body bag, opening the top to check to see if they could identify faces.

Military and commercial aircraft were delivering some aid and supplies to the region. But there was a desperate need for heavy equipment to reach possible survivors buried in collapsed buildings, including an eight-story hotel in Palu where voices were heard in the rubble.

A 25-year-old woman was found alive Sunday evening in the ruins of the Roa-Roa Hotel, according to the National Search and Rescue Agency, which released photos of the her lying on a stretcher covered in a blanket. A number of other survivors were still being found and a few were being pulled from buildings in different locations.

Meanwhile, an early warning system that might have prevented some deaths has been stalled in the testing phase for years.

The high-tech system of seafloor sensors, data-laden sound waves and fiber-optic cable was meant to replace a system set up after an earthquake and tsunami killed nearly 250,000 people in the region in 2004. But inter-agency wrangling and delays in getting just $69,000 to complete the project mean the system hasn't moved beyond a prototype developed with $3 million from the U.S. National Science Foundation.

"To me this is a tragedy for science, even more so a tragedy for the Indonesian people as the residents of Sulawesi are discovering right now," said Louise Comfort, a University of Pittsburgh expert in disaster management who has led the U.S. side of the project, which also involves engineers from the Woods Hole Oceanographic Institute and Indonesian scientists and disaster experts.

"It's a heartbreak to watch when there is a well-designed sensor network that could provide critical information," she said.

Beginilah wajah wilayah Donggala, Sulawesi Tengah yang luluh lantah paska #SulawesiEarthquake #PMISiapBantu pic.twitter.com/qkYPhbLgLg — Indonesian Red Cross (@palangmerah) September 30, 2018

After the 2004 tsunami killed 230,000 people in a dozen countries, more than half of them in the Indonesian province of Aceh, a concerted international effort was launched to improve tsunami warning capabilities, particularly in the Indian Ocean and for Indonesia, one of world's most earthquake and tsunami-prone countries.

Part of that drive, using funding from Germany and elsewhere, included deploying a network of 22 buoys connected to seafloor sensors to transmit advance warning.