SYDNEY, April 17 (Reuters) - An earthquake with a magnitude of 5.7 struck northwest of the South Pacific island nation of Vanuatu on Monday, the U.S. Geological Survey (USGS) said.
The quake was initially reported with a magnitude of 6.0 but was later downgraded by the USGS. It was recorded at a depth of 20 km (12 miles) and was located around 250 kms (150 miles) northwest of Vanuatu's Santo island, the USGS said.
There was no immediate tsunami warning or any reports of damage or casualties. (Reporting by Michael Perry; Editing by Paul Tait)