A 6.1 magnitude quake off the Philippine west coast shook the capital Manila and neighbouring areas on Thursday afternoon, but there were no reports of damage or casualties.
There was also no warning of a tsunami.
The United States Geological Survey (USGS) said the quake, centred around 66 miles (100 km) west of the port city of Batangas, south of Manila, happened at a depth of 45 miles (72 km) at around 1:30 p.m. (0530 GMT).
It had earlier said there were two quakes just seconds apart at much shallower depths.
"Normally with an earthquake that strong, any damage would be reported immediately. It's almost one hour since it happened and we have not received any significant report," said Glenn Rabonza, head of the Philippine National Disaster Coordinating Council.
Rabonza said the mayor of Lubang Island in Mindoro province, near the epicenter, had reported no damage.
"They're checking the bridges and other structures which swayed but were not damaged," he said.
Renato Solidum, head of the government's seismology agency, said the earthquake was caused by the movement of an active fault line called the Manila trench. The agency said the quake had a magnitude of 6 and happened at a depth of 25 km.
"We don't expect any significant damage because the highest intensity we recorded is only 5. Normally, a magnitude 6 quake and felt at intensity 7 could cause damage," Solidum said, adding the quake was not expected to generate a tsunami.
Residents in the capital, a sprawling city of about 13 million people, said they felt the tremor and that office buildings swayed.
"I was sitting at the computer when the ground started moving sideways. Nothing fell over or came down, but it swayed for what felt like a long time," said Caloy dela Pasion, a staffer at the Manila Bulletin newspaper.
"I felt quite dizzy. As soon as it was over, everyone came out of their offices feeling nervous."
Traffic in the Makati business district was flowing as usual and pedestrian numbers were normal.
"We all went down the building from the fourth floor. Some of us were scared," said 24-year-old Kath de Leon, an office worker in Makati.
Devi de Veyra was at home in her fifth-floor apartment in Manila's Quezon City when the quake hit.
"There was around 30-40 seconds of movement, a series of tremors. It was quite gentle but very eerie. I was waiting for the big quake to come, but it didn't," she said.
Quake strikes near Philippine capital
A 6.1 magnitude quake off the Philippine west coast shook the capital Manila and neighbouring areas on Thursday afternoon.