A tsunami watch has been issued for the entire Indian Ocean after a 8.7-magnitude earthquake off the coast of Indonesia's Aceh province.
The quake was recorded at a depth of 33km, 431km off the coast of Sumatra, the US monitors reported.
There is no threat to the Australian mainland or territories.
Reuters reports that locals in Aceh are fleeing to higher ground.
The earthquake was recorded at 2:38pm local time (6.38pm AEST).
If its current Richter scale measurement is proved accurate, the earthquake would be the eighth biggest recorded since 1900.
Aceh bore the brunt of the 2004 Boxing Day tsunami, which killed more than 230,000 people in 14 countries.
Nearly three-quarters of those killed by the 9.1-magnitude quake were from the Indonesian province.
26 Australians were among those killed by the 2004 natural disaster.
Indonesia straddles a series of fault lines that makes the vast island nation prone to volcanic and seismic activity.
More to come.