Evacuations were underway in the Philippines after an earthquake of at least magnitude 7.5 struck the southern region of Mindanao on Saturday night, triggering tsunami warnings in the country and in Japan.
The initial quake struck at a depth of 32 kilometres at 10:37pm local time (1:37am AEDT) about 21 kilometres north-east of Hinatuan municipality on Mindanao island, the United States Geological Survey (USGS) said.
The area was quickly hit by more than two dozen aftershocks, the largest measuring magnitude 6.5, according to the European-Mediterranean Seismological Centre (EMSC).
The initial quake triggered tsunami warnings and orders for coastal residents to flee to higher ground, though the US Tsunami Warning System later said the risk of large waves had passed.
The Philippine Institute of Volcanology and Seismology, Phivolcs, maintained that the risk of a tsunami remained.
'It's shaking again here now'
Evacuations were continuing in the Philippines, where there were no initial reports of significant wave damage or casualties despite the continuing aftershocks.
Waves of 40 centimetres were observed on Japan's Hachijojima island, some 290km south of Tokyo, according to the Japan Meteorological Agency, which had initially said they could reach a metre in height.
In Japan, authorities issued evacuation orders in various parts of Okinawa Prefecture, including for the entire coastal area, affecting thousands of people.
In the Philippines, Phivolcs urged people living near the coast of Surigao Del Sur and Davao Oriental provinces to evacuate or move farther inland.
It also revised earlier guidance to say it was expecting some damage from the tremor.
However, the two provinces are largely rural and not densely populated, unlike other parts of the Philippines.
Raymark Gentallan, police chief of the coastal town of Hinatuan, 30km from the earthquake's epicentre with a population of around 44,000, said power had been out since the quake struck.
"We're evacuating people away from coastal areas," he told Reuters, adding that disaster response teams had not yet seen any casualties or damage.
James Soria, who owns a small hotel in Hinatuan, said there had been significant damage to his home.
"It's shaking again here now," he told Reuters, before the call was disconnected as another aftershock hit.
Photographs posted on social media by Hinatuan's local administration showed scores of residents and queues of vehicles moving towards higher ground, with one large shelter occupied by several dozen people.
Cosme Calejesan, 47, who lives in Surigao City, 185km from the epicentre, said there had been damage to his house but the structure was still intact.
"I was already asleep, but I was woken up by the creaking sounds of my cabinets when the tremor occurred," he said.
"It was frightening. It was sudden and abrupt and I was worried for my children."
Earthquakes are common in the Philippines, which lies on the Ring of Fire, a belt of volcanoes circling the Pacific Ocean that is prone to seismic activity.
The EMSC said the quake of magnitude 7.5 had struck at a depth of 63km, while the US Geographic Survey put the quake at magnitude 7.6 and a depth of 32km.
ABC/wire