A powerful earthquake struck off the city of Padang on Indonesia's Sumatra island on today, killing up to 200 people and trapping thousands under rubble, an official said.
Priyadi Kardono, spokesman for the national disaster agency, said about 500 houses had caved in and people were buried under the rubble.
The 7.6 magnitude quake hit Padang, West Sumatra this afternoon. Initially thousands of people were believed trapped under collapsed houses and other buildings, but with communications to the area cut, officials have struggled to get details of casualties and damage.
The death toll was likely to rise as many buildings in the city of 900,000 people had collapsed, Indonesian vice president Jusuf Kalla told a late night news conference in Jakarta.
TV footage showed piles of debris and smashed houses after the earthquake, which caused widespread panic across the city.
Rustam Pakaya, the head of the health ministry's disaster centre in Jakarta, said "thousands of people are trapped in the rubble of buildings".
The main hospital had collapsed, roads were cut off by landslides and Metro Television said the roof of Padang airport had caved in. Thousands were expected to spend the night in the open while a full assessment of the damage would need to wait until daybreak.
The disaster is the latest in a spate of natural and man-made calamities to hit Indonesia, a sprawling archipelago of 226 million people.
Mr Kalla said the government was preparing for an emergency response of up to two months.
The damage could be on a par with that caused by a 2006 quake in the central Java city of Yogyakarta that killed 5,000 people and damaged 150,000 homes, he said.
The quake was felt around the region, with some high-rise buildings in Singapore, 440 km to the northeast, evacuating staff. Office buildings also shook in the Malaysian capital, Kuala Lumpur.
The Pacific Tsunami Warning Centre cancelled an earlier tsunami alert.
A resident called Adi told Metro Television: "For now I can't see dead bodies, just collapsed houses. Some half destroyed, others completely. People are standing around too scared to go back inside. They fear a tsunami."
"No help has arrived yet," he said. I can see small children standing around carrying blankets. Some people are looking for relatives but all the lights have gone out completely."
Sumatra is home to some of the country's largest oil fields as well as its oldest liquefied natural gas terminal, although there were no immediate reports of damage to those facilities.
Padang, capital of Indonesia's West Sumatra province, sits on one of the world's most active fault lines along the "Ring of Fire" where the Indo-Australia plate grinds against the Eurasia plate to create regular tremors and sometimes quakes.
A 9.15 magnitude quake, with its epicentre roughly 600 km northwest of Padang, caused the 2004 tsunami which killed 232,000 people in Indonesia's Aceh province, Thailand, Sri Lanka, India, and other countries across the Indian Ocean.
The depth of Wednesday's earthquake was 85 km, the United States Geological Survey said. It revised down the magnitude of the quake from 7.9 to 7.6.
A series of tsunamis yesterday smashed into the Pacific island nations of American and Western Samoa, and Tonga killing possibly more than 100 people, some washed out to sea, destroying villages and injuring hundreds.