PALU, Indonesia -- Two shallow earthquakes have occurred near the eastern Indonesian island of Sumba, but no tsunami warning was issued.

The temblors Tuesday occurred nearly 1,600 kilometers (990 miles) south of the area heavily damaged by a powerful earthquake and tsunami Friday on central Sulawesi island.

READ: Indonesian quake and tsunami devastates coast, many victims

The US Geological Survey said the first quake was magnitude 5.9 and the second one about 15 minutes later was magnitude 6.0.

State news agency Antara reported that one bridge was damaged in Wula Waijelu, but there were no other immediate reports of damage. About 750,000 people live on the island, located in eastern Indonesia in East Nusa Tenggara province near East Timor.

Indonesia is a vast archipelago stretching a similar distance to that between New York and London. It is located on the seismically active "Ring of Fire" and is frequently struck by earthquakes, volcanic eruptions and tsunamis. (AP)