A 8.9 magnitude earthquake has struck off Indonesia this afternoon.
A tsunami warning has been issued for Indonesia.
An Indonesian official says an earthquake with a preliminary magnitude of 8.9 has hit off Aceh.
Initial reports say the underwater quake struck 495kms off the west coast coast of northern Sumatra, occurring at a depth of 33kms.
Rippling tremors have been felt in Singapore, Thailand and Southern India.
The epicentre of the quake is close to where the 2004 Boxing Day quake hit, causing devastation.
Aceh was the worst-hit place in the tsunami. The Indonesian province lost 168,000 people out of a global total of 230,000 victims.
Australian Government Bureau of Meteorology says there is no current tsunami threat for Australia.
Updates:
(5:35 a.m. ET:) The power has gone out in Banda Aceh and residents are moving to higher ground, said Sutopo Purwo Nugroho, a spokesman for the Indonesian National Disaster Management Agency.
The extent of the damage is still being assessed.
In 2004, a 9.1-magnitude underwater earthquake struck off the coast of Sumatra, triggering a tsunami that killed more than 200,000 people in 14 countries. Aceh was one of the worse affected areas.
The tsunami, which washed away entire communities, caused nearly $10 billion in damage and more casualties than any other tsunami in history, according to the United Nations.
Indonesia is on the so-called Ring of Fire, an arc of fault lines circling the Pacific Basin that is prone to frequent earthquakes and volcanic eruptions.
(5:55 a.m ET:) The earthquake that struck Wednesday off the west coast of the Indonesian island of Sumatra was downgraded to a magnitude 8.6, the U.S. Geological Survey said.