Jakarta, Indonesia (CNN) Rescue workers in Indonesia continued a desperate search for survivors Sunday, two days after a powerful earthquake hit the island of Sulawesi and triggered a tsunami, killing more than 400 people.

After the 7.5-magnitude earthquake hit Friday, water smashed into buildings and swept away homes in the coastal city of Palu, home to 350,000 people.

Indonesian Disaster Management Agency spokesman Sutopo Purwo Nugroho put the death toll at 405 early Sunday, based on the number of bodies that had been recovered. More than 400 people were badly injured, Sutopo said.

Many victims were still buried under the rubble of buildings and houses, Sutopo said, and evacuation efforts were slowed by lack of heavy equipment and personnel.

Palu residents make their way along a street full of debris on September 29. Palu is a coastal city of about 350,000.

Palu residents make their way along a street full of debris on September 29. Palu is a coastal city of about 350,000.

Indonesian soldiers load emergency supplies onto a military plane at a base in Jakarta, Indonesia's capital, before heading to Palu on September 29.

Indonesian soldiers load emergency supplies onto a military plane at a base in Jakarta, Indonesia's capital, before heading to Palu on September 29.

Palu residents gather to look at a collapsed building in the aftermath of the quake and tsunami.

Palu residents gather to look at a collapsed building in the aftermath of the quake and tsunami.

A man searches for his belongings in the ruins of his house in Palu on Saturday, September 29.

A man searches for his belongings in the ruins of his house in Palu on Saturday, September 29.

The remains of a Palu building after it collapsed following the earthquake.

The remains of a Palu building after it collapsed following the earthquake.

Rescuers try to free a 15-year-old earthquake survivor who was trapped in the flooded ruins of a collapsed house in Palu on Sunday, September 30.

Rescuers try to free a 15-year-old earthquake survivor who was trapped in the flooded ruins of a collapsed house in Palu on Sunday, September 30.

Survivors rest outside the airport as they wait for a flight out of Palu on October 1.

Survivors rest outside the airport as they wait for a flight out of Palu on October 1.

Another scene of devastation in Palu. Homes, business and vehicles along the coast were washed away by violent tsunami waves. Roads and bridges were destroyed.

Another scene of devastation in Palu. Homes, business and vehicles along the coast were washed away by violent tsunami waves. Roads and bridges were destroyed.

An Indonesian soldier stands guard at a service station as people line up to fill gasoline containers on October 1.

An Indonesian soldier stands guard at a service station as people line up to fill gasoline containers on October 1.

The ruins of a collapsed mosque are seen in Palu on October 1.

The ruins of a collapsed mosque are seen in Palu on October 1.

A young girl cries outside the Palu airport after it reopened on October 1. Hundreds rushed to the airport hoping to catch one of the few flights out of the area.

A young girl cries outside the Palu airport after it reopened on October 1. Hundreds rushed to the airport hoping to catch one of the few flights out of the area.

People ride past a boat and other debris in Palu on October 1.

People ride past a boat and other debris in Palu on October 1.

Bodies are carried to a mass grave in Palu's Balaroa village on October 1.

Bodies are carried to a mass grave in Palu's Balaroa village on October 1.

A ship is stranded on the shore in Wani on October 1.

A ship is stranded on the shore in Wani on October 1.

An aerial view of a devastated area in Palu on Monday, October 1.

An aerial view of a devastated area in Palu on Monday, October 1.

A family on a motorcycle waits to learn the status of relatives on October 2.

A family on a motorcycle waits to learn the status of relatives on October 2.

A boy stands in front of a stranded ship in Donggala on October 2.

A boy stands in front of a stranded ship in Donggala on October 2.

Survivors scuffle for live chickens being distributed from a police truck in Palu on October 2.

Survivors scuffle for live chickens being distributed from a police truck in Palu on October 2.

People survey the wreckage of a bridge near Talise Beach in Palu.

People survey the wreckage of a bridge near Talise Beach in Palu.

A woman makes her way through rubble in the Palu neighborhood of Balaroa on October 2.

A woman makes her way through rubble in the Palu neighborhood of Balaroa on October 2.

A ship that was swept ashore during the tsunami rests near houses in Donggala on October 2.

A ship that was swept ashore during the tsunami rests near houses in Donggala on October 2.

People ride a scooter past a partially submerged mosque in Palu on October 2. The mosque was knocked from its foundation during the quake and tsunami.

People ride a scooter past a partially submerged mosque in Palu on October 2. The mosque was knocked from its foundation during the quake and tsunami.

A woman mourns in Palu on Tuesday, October 2, after her relatives were found to have died in the earthquake.

A woman mourns in Palu on Tuesday, October 2, after her relatives were found to have died in the earthquake.

Quake survivors salvage items from the debris of a factory complex in Palu.

Quake survivors salvage items from the debris of a factory complex in Palu.

A victim's face is bandaged at a makeshift hospital in Palu on October 3.

A victim's face is bandaged at a makeshift hospital in Palu on October 3.

This aerial image shows local residents lining up for gasoline in Palu on October 4.

This aerial image shows local residents lining up for gasoline in Palu on October 4.

Indonesian soldiers in Makassar prepare to welcome a military ship with evacuees on October 4.

Indonesian soldiers in Makassar prepare to welcome a military ship with evacuees on October 4.

Soldiers carry a dead body from the ruins of houses in Palu, Indonesia, on Thursday, October 4.

Soldiers carry a dead body from the ruins of houses in Palu, Indonesia, on Thursday, October 4.

Electricity and communications have been cut off, making it difficult to assess the damage in Palu and nearby fishing community of Donggala, Sutopo said.

"It is not just the people in the large urban areas. There are a lot of people also living in remote communities who are hard to reach" Jan Gelfand, head of the International Red Cross in Indonesia, told CNN.

With Palu airport closed, relief workers have to make their way to Palu by road. Sulawesi is one of the biggest islands in the world and the drive from the nearest airport is around 10-12 hours. "We already have people en route but you never know what damage there is to the road infrastructure."

In Palu, authorities urged residents to not go inside their homes Saturday night and to sleep away from buildings -- fields, roads or yards because of the danger from aftershocks.

Scores wounded, hospital calls for help

After a local hospital was damaged, medical staff opted to treat dozens of wounded residents just outside the building, Sutopo said.

Medical team help wounded residents outside a hospital in on Saturday.

Dr. Komang Adi Sujendra, Director of Undata Hospital in Palu was seeking help from the public following the quake.

"At the moment, in our hospital, electricity is out all over Palu, roads are cracked, the phone network doesn't work," he said in a video posted on Twitter. "We are hoping for any help."

"We need tents, medicine, canvas, nurses ..."

Air traffic controller dies after trying to escape

An air traffic controller who stayed behind to make sure a passenger airplane took off was among the dozens of victims.

Anthonius Gunawan Agung, 21, died in the hospital after he jumped off the traffic control tower at the Palu airport when he thought the tower was collapsing.

Telah wafat saat menjalankan tugasnya sebagai personel layanan navigasi penerbangan, Saudara Anthonius Gunawan Agung, Air Traffic Controller (ATC) AirNav Indonesia Cabang Palu pada Sabtu (29/09).#RIPAgung #DoaUntukSulteng#PrayforDonggala #PrayforPalu pic.twitter.com/6Wpobp3R7m — AirNav Indonesia (@AirNav_Official) September 29, 2018

His colleagues had evacuated the tower when they felt the earthquakes but he stayed behind to ensure that a Batik airplane safely took off, Air Nav Indonesia, the agency that oversees aircraft navigation, said in a statement.

"We felt a deep heartbreak, may God gives Anthonius the best place beside him, along with other victims of Donggala earthquake," Air Nav spokesperson Yohanes Sirait said.

A massive quake

The horrific scene began Friday when the first in a series of tremors was felt at 3 p.m. (3 a.m. ET) 35 miles (56 km) north of Palu, according to the United States Geological Survey.

Three quakes of 4.9 and larger magnitudes were recorded up to three hours before the tremor near Palu, the USGS said.

The tremor triggered a tsunami that hit beaches in the cities of Palu and Donggala, officials said.

The tsunami was "about three meters high," Nugroho said.

The shaking of the 7.5-magnitude tremor was "severe" and the likely damage following the quake was considered "moderate to heavy," the USGS said.

A series of aftershock quakes were reported in the aftermath of the quake, including a 5.8 magnitude tremor just 12 minutes later.

An early tsunami warning had been issued by the Indonesian meteorological agency, but was later lifted after the agency ascertained that the water had receded.

A resident is seen beside the collapsed brick wall of her house at Tobadak village in Central Mamuju, western Sulawesi province, on September 28 after a strong earthquake hit the area.

Indonesian President Joko Widodo said the military was being called in to the disaster-struck region to help search-and-rescue teams get to victims and find bodies.

Writing on his official Twitter account Friday, Widodo said he was monitoring the situation and preparing for any post-earthquake eventualities.

"May our brothers and sisters remain calm and be safe," he wrote.