Image: USGS

A shallow 6.4-magnitude earthquake struck off the Pacific island nation of Tonga on Thursday, the US Geological Survey reported, downgrading it from an earlier 6.7 reading.

The quake struck at a depth of 35 kilometres about 210 kilometres (130 miles) northeast of the country's capital, Nuku'alofa, where residents said they felt it but reported no damage.

The Pacific Tsunami Warning Centre said there was no danger of potentially hazardous waves in nearby coastal areas.