Jakarta: A 6.5-magnitude earthquake hit off the Indonesian island of Sumatra early Thursday, US seismologists said.
The quake struck at a depth of around 50 kilometres (30 miles) some 140 kilometres from the city of Padang, the US Geological Survey said.
The quake took place at 5:56 am local time (2256 GMT Wednesday), shortly before dawn, when many people would still have been in bed.
There was no immediate indication of whether the quake had caused any casualties or damage.
Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire," where tectonic plates collide.