SYDNEY, Australia - A magnitude 6.9 earthquake hit northern Papua New Guinea on Sunday morning, the United States Geological Survey said.

The Pacific Tsunami Warning Centre said there was "no tsunami threat" from the inland quake, which struck at 6:22 am local time (2022 GMT Saturday) at a depth of approximately 35 kilometres (21 miles).

The "notable quake" hit some 88 kilometres (54 miles) southwest of Wewak, the USGS said, a town of 25,000 people that serves as the capital of Papua New Guinea's East Sepik province.

There were no immediate reports of damage or injuries. The tremor was downgraded from an preliminary magnitude of 7.0.

Earthquakes are common in Papua New Guinea, which sits on top of the seismic "Ring of Fire" -- an arc of intense tectonic activity that stretches through Southeast Asia and across the Pacific basin.

Although they seldom cause widespread damage in the sparsely populated jungle highlands, they can trigger destructive landslides.

At least seven people were killed in April last year when a 7.0-magnitude quake hit a jungle-clad area in the country's interior.

Many of the island nation's nine million citizens live outside major towns and cities, where the difficult terrain and lack of sealed roads can seriously hamstring search-and-rescue efforts.