A total of 467 people were confirmed dead and 421 seriously injured in Wednesday's 7.6 magnitude quake, Tugiyo Bisri of the Social Affairs Ministry's crisis center said.
Wednesday's quake struck western Indonesia, trapping thousands of people under collapsed buildings — including hospitals, a hotel and a classroom, officials said.
The temblor Wednesday started fires, severed roads and cut off power and communications to Padang, a coastal city of 900,000 on Sumatra island. Thousands fled in panic, fearing a tsunami. It was felt hundreds of miles away in Malaysia and Singapore, causing buildings there to sway.
The undersea quake of 7.6 magnitude was followed by a powerful, shallow inland earthquake on Thursday morning with a preliminary magnitude of 6.8, the U.S. Geological Survey said. It hit about 150 miles south of Padang at a depth of just under 20 miles.
Shallow, inland earthquakes generally are more destructive. There were reports that the second quake badly damaged dozens of additional buildings.
Hundreds of buildings damaged
In Padang, the capital of West Sumatra province, the shaking was so intense from Wednesday's temblor that people crouched or sat on the street to avoid falling. Children screamed as an exodus of thousands of frantic residents fled the coast in cars and motorbikes, honking horns.
At least 500 buildings in Padang collapsed or were badly damaged, said Disaster Management Agency spokesman Priyadi Kardono, adding that 200 bodies had been pulled from the rubble there. The extent of damage in surrounding areas was still unclear due to poor communications. Indonesia, a poor, sprawling nation with limited resources, was cobbling together an emergency aid response, and the government was preparing for the possibility of thousands of deaths.
Padang's mayor appealed for assistance on Indonesian radio station el-Shinta.
"We are overwhelmed with victims and ... lack of clean water, electricity and telecommunications," Mayor Fauzi Bahar said. "We really need help. We call on people to come to Padang to evacuate bodies and help the injured."
Hundreds of people were trapped under collapsed buildings in Padang alone, including a four-star hotel, he said. Other collapsed or seriously damaged buildings included hospitals, mosques, a school and a mall.
"I was studying math with my friends when suddenly a powerful earthquake destroyed everything around me," an unidentified boy told the TVOne broadcaster. He escaped out of the top floor just as the three-story structure, used for after-school classes, crumpled.
TVOne footage showed heavy equipment breaking through layers of cement in search of more than 30 children it said were missing and feared dead.
Thousands were believed trapped throughout the province, said Rustam Pakaya, head of the Health Ministry's crisis center.