A second 6.8-magnitude quake rocked western Indonesia on Thursday as rescuers struggled to reach survivors of the previous day’s devastation.
Thousands are believed to be trapped under the rubble of buildings brought down by the 7.6-magnitude quake with an epicentre about 50 kilometres off the coast of Sumatra.
Officials warned that the death toll will continue to rise as the rubble is moved. At least 440 people have also been seriously injured.
"This is a high-scale disaster," Health Minister Siti Fadilah Supari told Metro TV. "I think it's more than thousands [dead], if we look at how widespread the damage is. But we don't really know yet."
Welfare Minister Aburizal Bakrie warned the damage caused by the quake could be similar to 2006 when a tremor in Java killed 5,000 people and damaged 150,000 homes.
Padang, a coastal city of 900,000 and capital of West Sumatra province, is the focus of relief workers. Of the 529 deaths that have been confirmed, 376 occurred in Padang.
Witnesses said the city is in chaos with fires still burning, buildings and markets collapsed, and water in the streets. Roadways are in gridlock as people try flee to higher ground. The airport in the city is open and witnesses said people are seeking shelter there and sleeping on mats while awaiting flights out of the region.
500 buildings destroyed
At least 500 buildings in Padang collapsed or were badly damaged in Wednesday's quake. More buildings have been damaged by Thursday's tremor, officials said.
At least 80 people were missing in the collapsed five-storey Ambacang Hotel in downtown Padang. As of Thursday afternoon, only two survivors and nine bodies had been found in the rubble.
At least 30 children are also missing in the debris of a school where they ...