A strong 6.2-magnitude earthquake struck eastern Indonesia on Tuesday, the US Geological Survey (USGS) said, but there was no tsunami warning or immediate reports of damage.

The offshore tremor struck at a shallow depth of 8.6 km, about 100 km southeast of Kupang, capital of the province of East Nusa Tenggara, the USGS said.

A string of deadly earthquakes that rocked Indonesia's Lombok island this summer killed over 500 people.

Indonesia, one of the most disaster-prone nations on earth, straddles the so-called Pacific "Ring of Fire", where tectonic plates collide and many of the world's volcanic eruptions and earthquakes occur.