Rescue workers are hunting for survivors after a powerful earthquake hit the Indonesian island of Sulawesi and triggered a tsunami, killing at least 384 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.

More than 540 people are being treated in several local hospitals amid the massive destruction in Palu and 29 people are missing.

The death toll could climb in the coming days, Disaster Management Agency spokesman Sutopo Purwo Nugroho warned.

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 are still urging residents to not go inside their homes and 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.

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.

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.

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.

The quakes come a month after a trio of earthquakes hit several islands in the South Pacific and Indonesia, including Lombok, which is still recovering from the effects of an August 5 earthquake that killed more than 430 people.