An undersea earthquake measuring 6.9 magnitude struck near the Solomon Islands in the South Pacific on Saturday, prompting a short-lived tsunami warning for the area.

The quake, initially recorded at 7.5 but later downgraded, struck at a depth of 33 km (20 miles) near the Solomon's Santa Cruz islands, said the U.S. Geological Survey.

The Pacific Tsunami Warning Center in Hawaii issued a warning, saying "hazardous tsunami waves from this earthquake are possible within 300 km (186 miles) of the epicenter along the coasts of the Solomon Islands".

But 30 minutes later, the Center said there was no longer a tsunami threat, but that small sea level fluctuations above and below the normal tide may continue for a few hours.