JAKARTA (AFP) - Two quakes were recorded in quick succession off the southern coast of Indonesia's Sumba island on Tuesday (Oct 2) morning, the United States Geological Survey said.

A shallow and moderately strong 5.9 quake struck at 2359 GMT (7.59 am, Singapore time), around 40km off Sumba, an island of some 750,000 people.

Sumba is situated opposite the island of Flores, with a population of over 1.8 million. Some reports had earlier described this earthquake as having occurred 250km south-west of Ende on Flores.

The first earthquake was followed, some 15 minutes later, by a stronger 6.0 magnitude quake in the same area at a depth of 30km.

Sumba lies some 1,600km to the south of Sulawesi island, which was struck by a devastating quake and tsunami last Friday.