Magnitude 7.6 and 6.1 earthquakes struck Papua New Guinea and Indonesia on Sunday.
In Papua New Guinea, the 6:46 a.m. quake struck about 67 km east of Kainantu, a sparsely populated area, and killed at least three people, the Associated Press reported.
The earthquake depth was registered at about 50-60 km.
Those killed in the Pacific nation died in a landslide in the gold mining town of Wau, the agency reported, citing Morobe province disaster director Charley Masange.
Other people were injured by falling buildings or debris, and some health centers, houses, country roads and highways were damaged, he said, adding it could take time to assess the full extent of the injuries and damage.
The Indonesian island of Mentawai, off the west coast of the island of Sumatra, recorded an earthquake with a depth of 40 km.
The extent of the damage is currently unclear. No casualties have been reported from the earthquake in Indonesia.
The US tsunami warning system issued a warning but later added that the threat was over. According to the Bureau of Meteorology, there was no immediate tsunami threat to Australia.
The latest tremors come a day after a series of powerful inland earthquakes rattled Indonesia’s West Papua province, with at least four measuring between magnitudes 6.2 and 5.5 recorded on Saturday.
Located in the eastern half of the island of New Guinea, east of Indonesia and north of eastern Australia, Papua New Guinea lies on the Pacific Ring of Fire, the arc of seismic faults around the Pacific Ocean where much of the world’s earthquake and volcanic activity occurs.
Renagi Ravu, a resident of Papua New Guinea, described the tremors and said he was meeting with two colleagues the morning the quake struck.
He tried to get up from his chair but couldn’t keep his balance and ended up in a kind of group hug with colleagues while plates and cups crashed to the floor.
His children, ages nine and two, had spilled their drinks and breakfast.
Mr Ravu, also a geologist, said he tried to calm everyone when the shaking lasted for more than a minute.
Aside from the deaths, the extent of the damage from the quake in the Pacific state was not immediately clear.
Mr Ravu said earthquakes were “common” in Wau, the city closest to the epicentre.
“But it usually doesn’t last as long and isn’t as violent as this one,” he added.
With a population of 10,000 and a scattered settlement in the highlands, he suspects more people could be affected. “It was pretty intense,” he said.
Damage to his property included a broken sewer pipe, he said, adding that his friends also shared pictures of cracked roads, broken pipes and fallen debris.
“They start cleaning their houses and streets,” he said. Communications appear to have been affected, he added, with some cellphone towers likely to have collapsed.
Some people also shared pictures and videos of items falling off supermarket shelves.
In early 2018, about 125 people died after a magnitude 7.5 quake hit the region, while in Indonesia in early February this year, about 25 people died after a magnitude 6.2 quake.
Additional reporting from wires