A 6.3 magnitude earthquake struck near the South Pacific Island nation of Tonga on Monday, the U.S. Geological Survey said.

The tremor hit at 2242 GMT Sunday and was centred about 89 kilometres (55 miles) north of Neiafu, an isolated island midway between Tonga's main island group and Samoa, at a depth of 36 kilometres (22 miles).

There were no immediate reports of damage and no tsunami risk reported.