The onshore quake hit the island of Tapat in the Molucca sea at a depth of 10 kilometres (6.2 miles) at 10:24 local time (0324 GMT), USGS said.

There were no immediate reports of casualties or damage on the island which has a population of around 50,000.

Indonesia's meteorology and geophysics agency said there was no tsunami threat.

The vast archipelago nation experiences frequent earthquakes due to its position on the Pacific "Ring of Fire", an arc of intense seismic activity where tectonic plates collide that stretches from Japan through Southeast Asia and across the Pacific basin.

A magnitude-6.2 quake that shook Sulawesi island in January 2021 killed more than 100 people and left thousands homeless.

In 2018, a magnitude-7.5 quake and subsequent tsunami in Palu on Sulawesi killed more than 2,200 people.

And in 2004, a magnitude-9.1 quake struck Aceh province, causing a tsunami and killing more than 170,000 people in Indonesia.