WELLINGTON: A magnitude 7.3 earthquake struck Tuesday just off the coast of Vanuatu in the South Pacific Ocean, the USGS said.

The quake occurred at a depth of 57 kilometers and was centred 30 kilometers west of Port Vila, the largest city in the island nation. The jolt was followed by a magnitude 5.5 aftershock near the same location.

It was not immediately clear whether it caused any damage, but Vanuatu government websites were offline in the aftermath of the quake and phone numbers for the police and other public agencies did not connect. Social media channels for the country's geohazards agency and the prime minister's office have not been updated.

A video posted on social media appeared to show a building that houses some diplomatic missions to Vanuatu — including those of Britain, France and New Zealand — with some damage to their structure, including buckled windows and debris that had crumbled from walls to the ground.

The USGS warned of tsunami waves for some coasts on Vanuatu, a group of 80 islands that is home to about 330,000 people. Waves could reach 0.3 meters to 1 meter (1 to 3 feet) above the tide level, the agency said.

Some islands in the low-lying atoll nation are 3 feet above sea level.

The USGS also warned of tsunami waves registering less than 0.3 meters (1 foot) above the tide level for a number of nearby Pacific Island countries including Papua New Guinea, Fiji and Solomon Islands.

Authorities in Australia and New Zealand, both located in the Pacific Ocean, said there was no tsunami threat to their countries.

New Zealand's Foreign Ministry said 37 New Zealanders were registered as being in Vanuatu. The ministry did not give details about the status of their nationals.