The epicentre of the quake was 48km south-southeast of the city of Singkil in Aceh province, at a depth of 37km, USGS said.

It occurred around 6.30am local time, and USGS revised it up from its initial measurement at 6.0 magnitude with a depth of 48km.

Indonesia’s Meteorology, Climatology and Geophysics Agency (BMKG) also put it at 6.2 and said there was no threat of a tsunami, while the country’s disaster agency said there were no immediate reports of casualties or major damage.

“The earthquake caused people to panic. It was felt between three and 10 seconds in four districts in Aceh and North Sumatra province,” Abdul Muhari, a spokesman for the BNPB disaster mitigation agency, said in a statement.

The European-Mediterranean Seismological Centre had a witness testimony saying the quake was “felt in Medan” — about 120km north-northeast of the epicentre.

Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire”, where tectonic plates collide.

On Nov 21, a 5.6-magnitude quake hit the populous West Java province on the main island of Java, killing 602 people.

Most of the victims were killed as buildings collapsed or landslides were triggered.

One of Sumatra island’s deadliest quakes occurred on Dec 26, 2004, setting off an Indian Ocean tsunami that killed more than 230,000 people including victims as far away as Sri Lanka, India and Thailand.

That powerful 9.1-magnitude quake triggered 30m waves that hit the shore of Banda Aceh on Sumatra.