An historic belfry, built during Spanish colonial rule in the Philippines, has been damaged following a powerful earthquake in the country's northern region today.

The Bantay Belfry was partially destroyed after the magnitude 7 quake shook Vigan City in Ilocos Sur province on Wednesday, July 27.

Footage shows chunks of the stone bell tower collapsing while tourists fled away from the falling rocks. The structure was built in the 1590s during the Spanish occupation in the Philippines, reportedly as a watchtower for pirates. Its name, Bantay, means 'guard' in the local language.

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) said the quake struck at 8:43 am local time three kilometres west-northwest of Tayum municipality in Abra province. It was recorded at a depth of 25 kilometres.

It was earlier pegged at a magnitude of 7.3, but was later downgraded to 7.0.

The earthquake was also felt in northern provinces and the capital region Metro Manila.

In a statement, Abra Representative Ching Bernos said the tremors had damaged homes and buildings in the province.

She said: 'I urge everyone to stay alert and to prioritize safety in light of the possibilities of aftershocks that might be felt after that strong earthquake. We are monitoring the situation on the ground and gathering information on the extent of the damage to the province.

'My office is also actively coordinating with proper authorities on what can be done to assist families and communities that were severely affected by this earthquake.'

The extent of the damage and the number of injuries or casualties is still being assessed by authorities.

PHIVOLCS has warned residents to be vigilant of aftershocks.