A 7.6 earthquake hit off the Philippine coast on Friday, triggering a tsunami warning for the eastern part of the archipelago and Indonesia, US seismologists said.
The US Geological Survey said the quake had a depth of 34 kilometres (21 miles) and hit at 8:47 pm (1247 GMT), 139 kilometres east of the city of Sulangan on Samar island.
The USGS had initially reported the quake as having a magnitude of 7.9, but revised it to 7.6.
The Pacific Tsunami Warning Center said in a bulletin any wave generated by the quake would be expected to hit Indonesia first, at 13:35 GMT.
It would then be due to hit the Philippines at 13:38 GMT. The times passed without immediate reports of damage.
"An earthquake of this size has the potential to generate a destructive tsunami that can strike coastlines in the region near the epicentre within minutes to hours," the center said.
The head of the Philippine Institute of Volcanology and Seismology (PHIVOLCS), Renato Solidum, said people living along the east coast of the country had been ordered to evacuate.
"It is a shallow quake and could trigger a tsunami so we have raised an alert," Solidum said on local radio.
"Waves could reach one metre high and as a precaution those living in coastal areas facing the sea should now evacuate and go to higher areas."
Another PHIVOLCS official said any potential wave may not hit until after 12:30 GMT, later than the Pacific Tsunami Warning Center's alert.
"So far we have not received any reports of a tsunami hitting anywhere in Indonesia," Suharjono, technical chief of Indonesia's Meteorology, Climatology and Geophysics Agency, who goes by one name, told AFP.
"We have heard about the Pacific warning and have alerted our disaster management agency in the Papua and Maluku provinces to be prepared for a possible evacuation in case there is a tsunami."
Tsunami warnings had also initially been raised for Japan, Taiwan and several Pacific islands, but they were quickly lifted.
Philippine authorities said the quake shook the eastern Philippines, but there were no immediate reports of damage or deaths.
"So far there are no casualties reported, but it was felt from the north to the south of the Philippines, on the eastern seaboard," civil defence chief Benito Ramos told AFP.