A 6.6-magnitude earthquake hit off the west coast of Indonesia's Sumatra island on Wednesday, seismologists said, sending terrified residents fleeing from homes and buildings.
The quake struck around 07:30 am (0030 GMT) some 300 kilometres (186 miles) southwest of Medan, the capital of North Sumatra province, at a depth of 45 kilometres, the US Geological Survey said.
There were no immediate reports of damage or casualties but a resident on Simeulue, a small island about 150 kilometres (93 miles) off Sumatra's west coast, said the ground shook violently for about a minute.
"People rushed out of their homes in panic. We felt strong shaking for about a minute, but so far there is no apparent sign of damage," said Abdul Karim, a 44-year-old civil servant in Sinabang, the capital of Simeulue island.
Indonesia's meteorology agency did not issue a tsunami warning and confirmed there were no reports of casualties or damage so far.
The Australian Bureau of Meteorology also said the Indonesian quake posed no tsunami threat to Australia.
Indonesia sits on the Pacific "Ring of Fire" where continental plates collide, causing frequent seismic and volcanic activity.