JAKARTA, Nov 12 (AFP) - A moderate 5.4-magnitude earthquake struck off Indonesia's Sumatra island early Friday but there were no immediate reports of damage and no tsunami warning was issued, seismologists said.

The quake struck at 2:39 am (1939 GMT Thursday), 140 kilometres (85 miles) southeast of Bengkulu at a depth of 35 kilometres, the United States Geological Survey said.

Indonesia sits on the Pacific "Ring of Fire," where the meeting of continental plates causes high volcanic and seismic activity.

A 7.6-magnitude quake that struck Sumatra island on September 30 killed more than 1,000 people.