SYDNEY (AFP) - A powerful 6.8-magnitude earthquake struck off the Pacific nation of Vanuatu on Friday, the United States Geological Survey (USGS) said, but no tsunami threat was detected.

The quake hit at a depth of 218 km, about 84 km from Vanuatu's capital Port Vila, the USGS said. The Pacific Tsunami Warning Centre said there was no threat of a tsunami.

The USGS originally put the magnitude at 6.9.