At least nine people have been killed and hundreds injured after an earthquake and aftershocks struck Indonesia, the country's disaster management office has said.
Hundreds of people fled their homes after the quake struck just after 6pm local time [1100 GMT], with an epicentre 100km southwest of the city of Bengkulu on the island of Sumatra.
Residents ran for higher ground as buildings collapsed in Padang, the capital of West Sumatra, and the town of Mukomuko, 300km from the quake's epicentre.
Electricity and phone lines were cut and buildings caught fire in Bengkulu, and people fled in Singapore as offices and homes were shaken.
India's government issued a tsunami alert for the Andaman Islands, while in Malaysia people were warned to stay away from beaches.
"Earthquakes of this size have the potential to generate a widespread destructive tsunami that can affect coastlines across the entire Indian Ocean Basin," the Pacific Tsunami Warning Centre said.
The centre said after the first quake that waves could strike Indonesia and Australia within an hour, with India and Sri Lanka possibly hit within three hours.
Sri Lanka also issued an alert for its north, south and eastern districts following the quake, the National Disaster Management Centre said.
The alerts were later withdrawn.
Indonesia, the world's largest archipelago, is located on the so-called Pacific "Ring of Fire," an arc of volcanoes and fault lines encircling the Pacific Basin, and is prone to earthquakes.
In December 2004, a powerful earthquake triggered a tsunami off the coast of Sumatra that killed more than 131,000 people in Indonesia's Aceh province.
Nearly one million peple are still struggling to rebuild their communities three years on and thousands remain dependent on outside aid.