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

The offshore tremor struck at a shallow depth of eight kilometres (five miles), about 100 kilometres southeast of Kupang on the Indonesian portion of Timor island, the USGS said.

A string of deadly earthquakes that rocked Indonesia's Lombok island this summer killed 555 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.

In 2004 a tsunami triggered by a magnitude 9.3 undersea earthquake off the coast of Sumatra in western Indonesia killed 220,000 people in countries around the Indian Ocean, including 168,000 in Indonesia.