A magnitude 7.7 earthquake in the South Pacific poses a tsunami risk for island nations such as Vanuatu and may affect Australia and New Zealand, authorities said.

The quake struck Friday southeast of the Loyalty Islands, which are about 380 kilometers (236 miles) south of Vanuatu capital city Port Vila, at a depth of 6 miles, according to the Pacific Tsunami Warning Center. Tsunami waves were possible within 1,000 kilometers of the epicenter along the coasts of Vanuatu, New Caledonia, Kiribati, Fiji and New Zealand, the center said.

“An earthquake of this size has the potential to cause destructive tsunami waves between 1 to 3 meters that can strike Vanuatu coastlines within minutes and more distant coastlines within hours,” the Vanuatu Meteorology and Geo-Hazards Department said in a statement. It advised people to immediately evacuate from coastal areas to higher ground.

Australia’s Bureau of Meteorology and New Zealand’s National Emergency Management Agency both posted tsunami watch alerts.

In New Zealand, strong currents and unpredictable surges were possible, NEMA said.

--With assistance from Jane Pong.