A magnitude 6.3 earthquake struck off the Vanuatu islands in the Pacific Ocean on Friday, the U.S. Geological Survey said, but local police said there were no immediate reports of damage or casualties.

The quake was centred 38 miles (60 km) west-northwest of Port Vila and had a depth of 33 miles, the USGS said.

"There was no damage and no casualties. We have not received any reports from the outer islands," a police official said by phone from Vanuatu.