The quake briefly prompted a tsunami alert for parts of Vanuatu, according to the U.S. Tsunami Warning System, which is part of the National Weather Service. As of 2:14 p.m. local time, U.S. officials said the threat had passed.

A magnitude 6.1 earthquake rattled buildings on Vanuatu's main island early Sunday but did not appear to have caused major damage, just days after a massive, deadly quake.

Commercial flights had been set to resume on Sunday before a new earthquake struck the island nation. Aid efforts remained strained because of the difficulty accessing the Pacific island.