JAKARTA: A 5.9-magnitude earthquake struck off the coast of the Indonesian island of Sumatra on Friday, the US Geological Survey said, but there were no immediate reports of damage or casualties.

The quake hit at six minutes after midnight (1706 GMT Thursday) 167 kilometres west of Bengkulu on the island's south-west coast, at a depth of 40 kilometres, the USGS said.

The Pacific Tsunami Warning Centre in Hawaii said there was no risk of a major tsunami, but warned that there could be localised problems.

"There is a very small possibility of a local tsunami that could affect coasts located no more than 100 kilometres from the earthquake epicentre," said a warning on its website.

"Authorities in the region near the epicentre should be made aware of this possibility." - AFP/de