Indonesian authorities raised to 385 on Saturday the number of people killed by earthquakes and a tsunami that struck the island of Sulawesi on Friday.

According to provisional data, there are also 540 injured and 29 missing, National Agency for Disaster Management (BNPB) spokesperson Sutopo Purwo Nugroho told a press conference in Jakarta, adding that thousands of buildings had been destroyed or damaged.

Sutopo said the number of casualties was likely to increase as the rescue mission continues and communication channels are re-established following the series of tremors, which included a magnitude 7.5 earthquake.

During the press conference, Sutopo displayed images of collapsed bridges, several destroyed buildings in coastal areas and dozens of injured on stretchers outside Undata hospital near the city of Palu.

The missing people are from the port of Pantoloan, located north of Palu, which was the most-affected city and appeared devastated in images distributed by the BNPB.

Sutopo said the local government is set to declare a state of emergency and stressed that the most important task was to restore power and communications to the region.

A shallow earthquake at a depth of 10 kilometers (6.2 miles) struck around 56km north of the city of Donggala early Friday evening, according to the United States Geological Survey. A tsunami followed, hitting beaches in Palu city and Donggala.

A magnitude 6.1 earthquake earlier on Friday in the same region killed at least one person, injured 10 and led to the collapse of a number of buildings.

Palu airport, which is used to operate national flights, has been shut since Friday after it was damaged by the quake, which has also affected bridges, hospitals and ports.

Sutopo said that airports in Poso, Tolitoli, Luwuk and Mamuju were open.

Mobile-phone videos shared through social media showed the moment the tsunami hit the coast as residents screamed and ran for safety. Sutopo said on Twitter on Saturday the tsunami was "about 3 meters high."

A team from the BNPB flew to Donggala with satellite communications equipment, Sutopo said, while the Indonesian Armed Forces and Police as well as other agencies were being deployed in Hercules aircraft to the site.

Health workers were caring for the injured at local hospitals.

The disaster follows on from the earthquakes and aftershocks between Jul. 29 and Aug. 19 on Lombok island where at least 557 people died and nearly 400,000 were displaced.

The country's deadliest earthquake with a magnitude of around 9.1 struck off the tip of Sumatra island in 2014, triggering a tsunami that killed nearly 280,000 people in Indonesia and other Indian Ocean nations.

The country sits on the Pacific Ring of Fire, an area of great seismic and volcanic activity, where some 7,000 earthquakes, mostly moderate, are recorded each year.