Rescuers continue to dig through rubble with their bare hands as the official death toll from the earthquake and tsunami that struck the Indonesian island of Sulawesi on Friday passed 840 people.

In the coastal community of Palu, an estimated 50,000 of the city’s 380,000 residents were displaced as a result of the magnitude 7.5 quake, which triggered a six-metre wall of water.

A 100-metre wide mass grave in the town has already been filled with more than 500 bodies.

An official said Monday that there may be hundreds more victims still buried under the debris and mud.

More than 3,000 people gathered at Palu’s airport Monday hoping to catch a ride out on a military plane but most were disappointed.

Video shows one woman at the airport crying out. “We have not eaten in three days,” she says. “We just want to be safe.”

In some other nearby communities, like Dongalla, aid workers are on the ground but rescuers have yet to arrive. Part of the problem is a lack of heavy equipment.

Damaged infrastructure is also making it difficult for Indonesian troops to get emergency food, water and medical supplies to the victims.

“We face many obstacles,” said Sutopo Nugroho, spokesperson for the Indonesian Disaster and Mitigation Agency, at a media briefing Monday.

Cellphone towers were toppled in the quake, which has hampered communication. It may also have prevented text messages meant to warn about the impending tsunami from reaching citizens.

Meanwhile, questions are being raised about why the country’s meteorological agency lifted the tsunami warning just over half an hour after the quake, possibly making a bad situation worse.

With a report from CTV’s Omar Sachedina in Jakarta, Indonesia and files from The Associated Press