A 7.7 magnitude earthquake struck off Papua New Guinea on Monday, US official monitors said. A tsunami warning was issued later.
The quake hit at a depth of 65 kilometres, nearly 54 kilometres from the nearest city of Kokopo Panguna on New Britain Island and 789 kilometres from the capital Port Moresby, the United States Geological Survey reported.
No destructive, Pacific-wide tsunami was expected though, it said.
Earthquakes of a 6.0 magnitude and above are considered strong and can lead to human casualties and the destruction of infrastructure.
Papua New Guinea is located in the so-called Ring of Fire quake zone. It has been hit by devastating earthquakes in the past, most notably in July, 1998, when a quake led to an undersea landslide and a tsunami, killing over 2,200 people.