An earthquake of at least magnitude 7.5 struck Mindanao in the southern Philippines late on Saturday, triggering evacuation orders for some areas and southwestern Japanese coasts because of warnings of tsunami waves of a 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.
The U.S. Tsunami Warning System said there could be waves of up to 3 metres above the tide level along some Philippine coasts.
"Boats already at sea during this period should stay offshore in deep waters until further advised," Phivolcs said, asking people living near the coast of Surigao Del Sur and Davao Oriental provinces to "immediately evacuate" or "move farther inland".
The Japanese broadcaster NHK said tsunami waves of up to a metre were expected to reach Japan's southwestern coast around 30 minutes later - by 1:30 a.m. on Sunday (1630 GMT on Saturday).
Phivolcs said it did expect significant damage from the tremor itself, but warned of aftershocks.
Raymark Gentallan, local police chief of the coastal town of Hinatuan near the earthquake's epicentre, said power has been knocked out since the quake struck, but disaster response teams have not monitored any casualties or damage yet.
{{/usCountry}}Raymark Gentallan, local police chief of the coastal town of Hinatuan near the earthquake's epicentre, said power has been knocked out since the quake struck, but disaster response teams have not monitored any casualties or damage yet.
{{/usCountry}}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).