SYDNEY, Australia - A strong earthquake struck under the sea floor near the South Pacific nation of Tonga on Monday, theU.S. Geological Survey said. No damage or tsunami threat was reported.

The magnitude-6.2 temblor hit shortly before 2 a.m. six miles under the sear floor about 170 miles south of Nuku'alofa, Tonga's capital, the USGS said.

The Hawaii-based Pacific Tsunami Warning Center, which maintains an ocean-wide wave warning system, did not issue a tsunami warning bulletin.