SUVA -- A 7.0-magnitude earthquake jolted 79 km SSE of Pangai, Tonga at 01:18 local time on Monday (12:18 GMT Sunday), the US Geological Survey said.

The US Tsunami Warning Center issued an alert saying hazardous waves could be possible, but later said there was no longer a tsunami threat.

The epicenter, with a depth of 10.0 km, was initially determined to be at 20.495 degrees south latitude and 174.111 degrees west longitude.

There were no immediate reports of casualties or damage. A local resident told Xinhua that the earthquake was felt strongly in the capital Nuku'alofa, but his house was not damaged at all.

Pacific island countries such as Fiji, Tonga and Vanuatu lie on the so-called Pacific "Ring of Fire," an arc of earthquake and volcanic zones where continental plates collide, producing frequent seismic activities.