MAKASSAR (AGENCE FRANCE-PRESSE, REUTERS) - Indonesia was rocked by a powerful 7.5-magnitude earthquake on Friday (Sept 28), with the national disaster agency saying that "many" buildings had collapsed in the aftermath of the huge tremor.
There were no immediate reports of deaths or injuries.
A tsunami wave of up to 2m hit the shoreline of Palu city after the quake.
"There are reports that many buildings collapsed in the earthquake," national disaster agency spokesman Sutopo Purwo Nugroho said in a statement. "Residents panicked and scattered out of their homes."
Pictures supplied by the agency showed a badly damaged shopping mall in the city of Palu where at least one floor had collapsed onto the one below.
Other pictures showed major damage to buildings, with rubble strewn about the road and large cracks running through the pavement.
Search and rescue teams have been dispatched to hard-hit areas, Nugroho said.
The quake hit central Sulawesi island at a shallow depth of about 10km, the US Geological Survey said, just hours after a smaller jolt killed at least one person in the same part of the country. Earlier reports indicated the quake's magnitude was 7.7.
The disaster agency briefly issued a tsunami warning before lifting it.
AFP phone calls to several regional hospitals went unanswered.
The latest quake was a higher magnitude than those that killed hundreds on the island of Lombok earlier this year.
Friday's tremor was centred 78km north of Palu, the capital of Central Sulawesi province, but was felt in the far south of the island in its largest city Makassar and on the neighbouring island of Kalimantan, Indonesia's portion of Borneo island.
The initial tremor struck as evening prayers were about to begin in the world's biggest Muslim-majority country on the holiest day of the week when mosques would be especially busy.
It was followed by a series of powerful aftershocks, including one measuring magnitude 5.7.
"I was about to start prayers but then I heard people shouting 'earthquake! earthquake!' so I stopped," Andi Temmaeli from Wajo, south of Palu, told AFP.
Lisa Soba Palloan, a resident of Toraja, also south of Palu, said locals felt several quakes on Friday.
"The last one was quite big," she said. "Everyone was getting out their homes, shouting in fear."
Indonesia is one of the most disaster-prone nations on earth.
The South-east Asian archipelago nation lies on the Pacific "Ring of Fire", where tectonic plates collide and many of the world's volcanic eruptions and earthquakes occur.
This summer, a series of powerful quakes hit Lombok, killing over 550 people on the holiday island and neighbouring Sumbawa.
Some 1,500 people were injured and about 400,000 residents were displaced after their homes were destroyed.
Indonesia has been hit by a string of other deadly quakes including a devastating 9.1-magnitude tremor that struck off the coast of Aceh, in Sumatra in 2004.
That quake triggered a tsunami that killed 220,000 throughout the region, including 168,000 in Indonesia.
The Boxing Day disaster was the world's third-biggest quake since 1900, and lifted the ocean floor in some places by 15m.
Indonesia's Aceh province was the hardest hit area, but the tsunami affected coastal areas as far away as Africa.
Among the country's other big earthquakes, a 6.3-magnitude quake in 2006 rocked a densely populated region of Java near the city of Yogyakarta, killing around 6,000 people and injuring 38,000.
More than 420,000 people were left homeless and some 157,000 houses were destroyed.
A year earlier, in 2005, a quake measuring magnitude 8.7 struck off the coast of Sumatra, which is particularly prone to quakes, killing 900 people and injuring 6,000.
It caused widespread destruction on the western island of Nias.