Manila: An earthquake of at least magnitude 7.5 struck Mindanao in the southern Philippines late on Saturday, triggering evacuation orders for some areas of the country and for southwest Japanese coasts because of warnings of tsunami waves of 1 metre (3 feet) or more.
The Philippine Seismology Agency Phivolcs said the waves could hit the Philippines by midnight (1600 GMT) and continue for hours, though there were no initial reports of significant wave damage by that time.
The USTsunami Warning System said there could be waves of up to 3 metres above the usual high tide level along some Philippine coasts, though it subsequently said there was no risk of a tsunami.
"Based on all available data ... the tsunami threat from this earthquake has now passed," it said.
Phivolcs said people living near the coast of Surigao Del Sur and Davao Oriental provinces should "immediately evacuate" or "move farther inland".
"Boats already at sea during this period should stay offshore in deep waters until further advised," it said.
The two provinces are largely rural and not densely populated, unlike other parts of the Philippines.
Japanese broadcaster NHK said tsunami waves of up to 1 metre were expected to reach Japan's southwest coast by 1:30 a.m. Sunday (1630 GMT Saturday).
Phivolcs said it did not expect significant damage from the tremor itself, but warned of aftershocks.
The area has already been hit by more than a dozen aftershocks, the largest measuring at magnitude 6.4, according to the European-Mediterranean Seismological Centre (EMSC).
Raymark Gentallan, local police chief of the coastal town of Hinatuan near the earthquake's epicentre and which has a population of around 44,000, said power has been knocked out since the quake struck, but disaster response teams had not yet monitored any casualties or damage.
"We're evacuating people away from coastal areas," he told Reuters.
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.
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 European-Mediterranean Seismological Centre (EMSC) said a quake of magnitude 7.5 had struck at a depth of 63 km (39 miles).
The U.S. Geographic Survey put the quake at magnitude 7.6 and a depth of 32 km (20 miles), and said it had struck at 10:37 p.m., Philippines time (1437 GMT).