A magnitude 6.2 aftershock rocked Indonesia's Lombok on Thursday, sparking fresh panic on the tropical tourist island as the official death toll from a powerful earthquake four days earlier almost doubled to at least 319.
Reuters witnesses reporting on the aftermath of Sunday's quake in the north of the island said buildings and walls that had already been weakened collapsed, and people ran out onto roads even as rocks tumbled down from hillsides.
"Evacuees and people ran out of houses when they felt the strong shake of the 6.2 magnitude quake," Sutopo Purwo Nugroho, a spokesman for Indonesia's disaster mitigation agency (BNPB), said on Twitter. "People are still traumatised. Some buildings were damaged further because of this."
Officials said the epicentre of the aftershock was on land and so there was no risk of a tsunami.
The United States Geological Survey recorded the latest quake at 5.9, at a depth of 10 km (six miles).
"Our latest update is that 319 people died," said Indonesia's chief security minister Wiranto, who like many Indonesians goes by one name, adding that rescue efforts were ongoing and complicated by aftershocks.
"This number will continue increasing as rescue teams continue to find victims under collapsed buildings," BNPB said in a statement.
More on Lombok quake:
Indonesia's Lombok island hit by third earthquake causing buildings to collapse
Dubai residents describe Indonesia earthquake horrors
Collapsed mosque centre of rescue operation to save worshippers in Lombok
A humanitarian crisis is also looming in Lombok, where thousands have been left homeless and in desperate need of clean water, food, medicine and shelter.
Authorities made announcements over loudspeakers at evacuation sites, urging people to remain calm and stay inside tents or find open space if they were inside or near buildings.
"Please stay calm, this is just an aftershock and it will be over soon, there's no need to be scared," one official announced.
Officials said about three-quarters of Lombok's rural north had been without electricity since Sunday, although power had since been restored in most areas before the aftershock. Aid workers have found some villages hard to reach because bridges and roads were destroyed.
Ruslan, a 29-year-old resident of Pemenang on the northwestern shoulder of Lombok, said he had already been anxious about aftershocks before the latest jolt.
"My heart jumps if even the door slams hard. It's difficult to get used to," he said. "We are still scared to go into the house. At the most, we go in quickly to grab something and then run back out."
Thousands of tourists have left Lombok since Sunday, fearing further earthquakes, some on extra flights provided by airlines and others on ferries to the neighbouring island of Bali.
Indonesia sits on the Pacific Ring of Fire and is regularly hit by earthquakes. In 2004, the Indian Ocean tsunami killed 226,000 people in 13 countries, including more than 120,000 in Indonesia.