There were no immediate reports of serious injuries or deaths from the quake, which struck about 11 km (six miles) southeast of the town of Dolores and at a shallow depth of 10 km (6 miles).
A hospital in Abra province was evacuated after the building partially collapsed following the quake, but there were no casualties reported, said officials.
Abra governor Joy Bernos posted photos of the damaged Abra provincial hospital on her Facebook account which showed a gaping hole in the front entrance facade. Other photos showed hospital beds, including one with a patient, wheeled across the road and evacuated hospital staff.
“We are still experiencing aftershocks. We have received reports of damages to houses. But so far no casualties,” said Mayor Rovelyn Villamor in the town of Lagangilang in Abra province.
“We don’t have power supply because that’s automatically cut off due to danger,” Villamor told DZRH radio.
Renato Solidum, director of the state seismology agency, told DZRH radio station, said strong aftershocks were expected.
“The focus of attention is on Abra and nearby provinces. This is a major earthquake,” Solidum said, adding that landslides had been reported in some parts of Abra, particularly in the town of Manabo.
Abra, home to nearly 250,000 people, is a landlocked province in the northern Philippines. Its deep valleys and sloping hills are enclosed by rugged mountains.
Eric Singson, a congressman in Ilocos Sur province, also in the north, told DZMM radio station the quake had been felt strongly there.
“The earthquake lasted 30 seconds or more. I thought my house would fall,” said Singson.
“Now, we are trying to reach people …. Right now there are aftershocks so we are outside our home.”
The quake was also felt in Manila where several buildings were evacuated, with some people forced to flee from the 30th floor of one building, and the city’s metro rail systems were halted at rush hour.
The Philippines is prone to natural disasters and is located on the seismically active Pacific “Ring of Fire”, a band of volcanoes and fault lines that arcs round the edge of the Pacific Ocean.
(Reporting by Jose Joseph and Jahnavi Nidumolu in Bengaluru; Writing by Ed Davies: Editing by Himani Sarkar and Michael Perry)