PADANG, INDONESIA » A second powerful earthquake rocked western Indonesia today as rescuers struggled to reach survivors of the previous day's temblor, which killed at least 467 people and left thousands trapped under collapsed buildings.

The death toll from yesterday's undersea quake of 7.6 magnitude was expected to rise further after rescuers dig through the rubble in heavily populated towns of Sumatra island.

The second, a shallow inland quake of 6.8-magnitude, damaged additional buildings today. The U.S. Geological Survey said the inland quake hit about 150 miles south of Padang at a depth of just under 20 miles.

“;This is a high-scale disaster,”; Health Minister Siti Fadilah Supari told Metro TV.

The temblor yesterday 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.

In Padang, the capital of West Sumatra province, the shaking was so intense from yesterday's temblor that people crouched or sat on the street to avoid falling. 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. Indonesia, a sprawling nation with limited resources, was cobbling together an emergency aid response, 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.

Search-and-rescue teams were working in heavy rain when the second strong quake struck, causing widespread panic and badly damaging 30 houses in Jambi, another Sumatran town. It was not clear if there were injuries, but frantic parents could be seen rushing to schools in search of their children.

Indonesia's government announced $10 million in emergency response aid, and medical teams and military planes were being dispatched to set up field hospitals and distribute tents, medicine and food rations.

Local television reported more than two dozen landslides. Some blocked roads, causing miles-long traffic jams of cars and trucks.