South-east Asian nations issued tsunami alerts and urged people to move to safety away from coastlines after a massive 8.7 magnitude earthquake struck off the coast of Sumatra on Wednesday.
US monitors issued an Indian Ocean-wide tsunami watch after the quake, which according to the US Geological Survey struck off the coast of Sumatra at 2:38 pm (0838 GMT) at a depth of 33 kilometres.
USGS had initially reported it as an 8.9-magnitude quake.
Sri Lanka and India issued tsunami warnings while Thailand urged people on the Andaman coast, a popular tourist destination, to move to safety.
A Sri Lanka government statement said waves could hit the island's eastern coast by about 10:40 GMT and urged an orderly evacuation of the coastal strip.
India added the coastal states of Kerala, Orissa, Goa and West Bengal to a tsunami warning along with Andhra Pradesh and Tamil Nadu. A more urgent "red alert" warning was earlier issued for the Andaman and Nicobar Islands, located in the Indian Ocean.
"We have evacuated a few hundred people. There is no report of any damage so far," Shakti Sinha, chief secretary of Andaman and Nicobar islands, told AFP by telephone.
Thailand's National Disaster Warning Centre advised people in the area to move to higher places and stay as far away as possible from the sea. The quake swayed buildings as far away as Thailand's capital Bangkok.
Australian Bonnie Muddle, vacationing in the Thai resort island of Phuket at the time of the quake, said people were being evacuated from popular tourist areas including Krabi and Phang nag bay.
"Everyone is getting a little concerned over here," she told AFP.
On December 26, 2004 a 9.2-magnitude earthquake off Sumatra generated a catastrophic tsunami that wrought devastation across southern Asia, killing an estimated 220,000 people.
Last year, a 9.0-magnitude earthquake caused a tsunami and nuclear disaster in Japan, killing some 19,000 people.
On Wednesday Japan's Meteorological Agency said that there was no risk of a tsunami affecting Japanese coasts.
Geoscience Australia, Canberra's geohazards agency, said there was no risk to Australia from the jolt. Taiwan and New Zealand also said the earthquake posed no threat to the respective countries.