The shallow 6.5-magnitude quake levelled hundreds of homes, mosques and businesses across Aceh province.
The shallow 6.5-magnitude quake levelled hundreds of homes, mosques and businesses across Aceh province, one of the areas worst affected by the devastating 2004 tsunami.
Search and rescue crews using advanced life-detecting devices have been combing the rubble for any sign of movement, as hopes fade of finding any more survivors more than a day after the quake.
"These scan through the rubble to see if anyone's alive or dead," national disaster agency spokesman Sutopo Purwo Nugroho told AFP.
The death toll stands at 99, he added. The figure has fluctuated as authorities identify the dead across the region.
Thousands of soldiers and emergency personnel have been using excavators to clear rubble in the worst-hit areas, with volunteers -- equipped with little more than hoes and their bare hands -- also chipping in.
President Joko Widodo asked all Indonesians to pray for their countrymen in the disaster-stricken province.
"Aceh is not alone," he posted on his official Twitter account.
But attention is shifting to caring for those injured and homeless.
The army has established kitchens, shelters and a field hospital in the hard-hit town of Meureudu, Aceh military chief Tatang Sulaiman told AFP.
"Our priority today is to re-check all the buildings to ensure no more victims are trapped, and to help the refugees," he said.
But medical supplies and other essentials in short supply, officials said, with the region's ill-equipped hospitals overwhelmed.
More than 700 people were injured in the quake, many seriously, according to the disaster agency.
Said Mulyadi, the deputy chief of the worst-hit Pidie Jaya district, said they were in desperate need of medicine, supplies and extra hands to treat the injured.
"We need surgeons and orthopaedics, because many victims have fractures," he told AFP.
Most victims spent the night outdoors, either unable to return to their homes or terrified of the aftershocks rattling the region, he added.
Aid has begun trickling into the region, with emergency shelters erected to house those left with nowhere to go.
But more was needed for the 4,000 people evacuated to shelters, said local disaster agency chief Puteh Manaf.
Many fled for higher ground when the quake struck, fearing a tsunami, though no alert was issued.
A huge undersea earthquake in 2004 triggered a tsunami that engulfed several countries around the Indian Ocean, killing more than 170,000 people in Indonesia alone, the vast majority in Aceh.
Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire", where tectonic plates collide.
Aceh lies on the northern tip of Sumatra island, which is particularly prone to quakes.
In June a 6.5-magnitude quake struck off the west of Sumatra, damaging scores of buildings and injuring eight people.