A powerful earthquake struck off the west coast of Indonesia's Sumatra island early on Monday and was felt strongly in some areas, including the city of Padang, though there were no immediate reports of casualties or damage, officials said.
The magnitude 6.7 quake, which struck at 04:09 local time, did not have the potential to cause a tsunami, the head of Indonesia's geophysics agency (BMKG) Dwikorita Karnawati said.
The European Mediterranean Seismological Centre (EMSC) had put the strength of the earthquake near Kepulauan Batu at 6.8 magnitude, at a depth of 40 km.
The Indonesian BMKG agency described the quake as feeling like a "truck passing through" in some areas, and said there had been four aftershocks with the biggest of magnitude 6. Padang is about 1,000 km north west of capital Jakarta.
So far officials had not received any information on damage, but were still assessing the impact in some remote areas including north Sumatra's Nias Selatan, where communications were difficult, an official said.
Indonesia suffers frequent earthquakes, straddling the so-called "Pacific Ring of Fire", a seismically active zone where different plates of the earth's crust meet.