SUVA, May 25 (Xinhua) -- A 6.0-magnitude earthquake jolted 178 km SSW of 'Ohonua, Tonga at 23:49 local time on Sunday, the U.S. Geological Survey (USGS) said.
There were no immediate reports of casualties or damage.
The epicenter, with a depth of 11.6 km, was initially determined to be at 22.788 degrees south latitude and 175.725 degrees west longitude, according to the USGS.
The Pacific Tsunami Warning Center did not immediately issue a tsunami warning based on the quake.
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.
