An earthquake survivor trapped in a collapsed hotel in western Indonesia sent a text message saying he and some others were alive, triggering a frantic rescue operation, but hopes faded Saturday as sniffer dogs failed to detect life.

Padang's police chief said voices and claps were heard from survivors buried in the Ambacang Hotel since Wednesday's 7.6-magnitude quake, which killed at least 715 people. He said one survivor — who had been staying in Room 338 — sent a text message to relatives Friday, saying he and some others were still alive.

But frantic rescue efforts came up empty Saturday as sniffer dogs failed to detect life.

After several hours of digging through blocks of concrete, steel and bricks, rescue workers gave up. Padang police chief Col. Boy Rafli Amar told reporters, "So far rescuers have found nothing."

Hidehiro Murase, head of a Japanese search dog team, said its search had been fruitless.

"We did an extensive search this morning, but there were no signs of life. Our dogs are trained to smell for living people, not the dead, and they didn't sense anything," he told the AP.

Three thousand others remain trapped or missing. That number could rise as four villages were wiped out from earthquake-triggered landslides, where 644 people are feared buried. If all 644 are dead, the death toll could top 1,300.

The quake devastated more than 60 miles along the western coast of Sumatra island, prompting a huge international aid operation in a country that sits on a major geological fault zone and has dozens of quakes every year.

More than 20,000 houses and buildings were destroyed and 2,400 people hospitalized across seven districts, said Priyadi Kardono, a spokesman for the national disaster agency.

Block after block of toppled hotels, hospitals, office buildings and schools had yet to be searched in Padang, a port city of 900,000 people. Dozens of unclaimed corpses were laid out in the scorching sun at Dr. M. Djamil General Hospital, Padang's biggest, which was damaged in the quake.

Eric van Druten, a 31-year-old Australian surfer, said several of his friends were staying at the Ambacang and another hotel. He said he ran toward the swimming pool when the earthquake began to shake the building.

"But the wall collapsed, so we had to get out. There is still a heap of people in the pool," he said.

On Thursday, rescuers pulled out two women — a student and a teacher — from the debris of the Foreign Language School of Prayoga.

The teacher, Suci Ravika Wulan Sari, was extracted almost exactly 48 hours after the college crumbled in the 5:16 p.m. quake, killing dozens of students.

"She was conscious. Only her legs and fingers are swollen because she was squeezed," said the institute's director, Teresia Lianawaty. "Thank God! It is a miracle."

Eight hours earlier, 19-year-old student Ratna Kurniasari Virgo was pulled out. For 40 hours she had laid trapped with a broken leg between the collapsed walls of her college and the bodies of her dead friends.

"Her dead friends were beneath and above her. Fortunately, she was able to withstand the stench for 40 hours," said Dubel Mereyenes, the doctor who treated her. "She has a severely injured leg, but we will try to avoid amputation."

Fuel was being rationed amid a power outage, water and food were in short supply and villagers dug out the dead with their bare hands.

As the scale of the destruction became clearer, Vice President Jusuf Kalla told reporters in the capital, Jakarta, that the recovery operation would cost at least $400 million.

Military and commercial planes shuttled in tons of emergency supplies, although rural areas remained cut off due to landslides that reportedly crushed several villages and killed nearly 300 people.

While the damage was most severe around Padang, an Associated Press reporter saw virtually no remaining structures in the rural, hilly district of Pariaman, a community of about 370,000 about 50 miles to the north.

Landslides had wiped away roads and there was no sign of outside help.

In Padang, President Susilo Bambang Yudhoyono told a crowd of people whose relatives are missing to "please be patient," assuring them the government was doing everything in its power to save lives.

Millions of dollars in aid and financial assistance came from Australia, Britain, China, Germany, Japan, the European Union, Malaysia, the Netherlands, Singapore, South Korea, Switzerland, Denmark and the United States, Indonesian officials said.

Wednesday's quake originated on the same fault line that spawned the 2004 Asian tsunami that killed 230,000 people in a dozen nations.

The Associated Press contributed to this report.