A strong, shallow earthquake shook Indonesia’s Sulawesi island just after midnight, causing landslides and sending people fleeing from their homes in the nighttime darkness.
At least 34 people have been killed and hundreds injured, authorities said.
"The latest information we have is that 26 people are dead, all in Mamuju city," said Ali Rahman, head of the local disaster mitigation agency, referring to a city of some 110,000 in West Sulawesi province.
"That number could grow but we hope it won't... Many of the dead are buried under rubble."
Separately, the national disaster agency said at least eight people had died in an area south of Mamuju.
Indonesian officials said they were still collecting information from devastated areas.
Rescuers searched for more than a dozen patients and staff trapped beneath the rubble of a hospital in Mamuju that was flattened.
"The hospital is flattened - it collapsed," said Arianto from the rescue agency in Mamuju city, who goes by one name.
"There are patients and hospital employees trapped under the rubble and we're now trying to reach them," he added, without giving a specific figure.
Rescuers were also trying to reach a family of eight trapped under the rubble of their destroyed home, he added.
In a video released by the National Disaster Mitigation Agency, a girl trapped in the wreckage of a house cried out for help and said her mother was alive but unable to move out.
"Please help me, it’s hurt," the girl told rescuers, who replied that they desperately wanted to help her.
In the video, the rescuers said an excavator was needed to save them. Other images in the video showed a severed bridge and damaged and even flattened houses.
The country's search-and-rescue agency earlier said at least one hotel had collapsed after the quake struck at 2.18 am local time on Friday (1818 GMT Thursday).
It later clarified that the hotel had partially caved in, while the regional governor's office also suffered extensive damage.
Another video showed a father crying, asking help from people to save his children buried under tons of his house rubble. "My children there... they are trapped inside, please help," he cried in panic.
About 2,000 displaced people were evacuated to several temporary shelters. The magnitude 6.2 quake early on Friday was centred 22 miles south of West Sulawesi province’s Mamuju district, at a depth of 11 miles, the US Geological Survey said.
At least 62 houses, a public health centre and a military office were damaged in Mamuju and landslides were set off in three locations and blocked a main road connecting Mamuju to the Majene district, said Raditya Jati, the disaster agency’s spokesperson.
He said the agency was still collecting data from areas struck by the quake
On Thursday, a magnitude 5.9 quake hit under the sea in the same region, damaging several homes but causing no apparent casualties.
Indonesia, a vast archipelago of 260 million people, is frequently struck by earthquakes, volcanic eruptions and tsunamis because of its location on the "Ring of Fire," an arc of volcanoes and fault lines in the Pacific Basin.