Itbayat has a population of about 2,800 people and lies in the Luzon Strait that separates the Philippines and Taiwan.

Two strong earthquakes hours apart struck a group of sparsely populated islands in the Luzon Strait in the northern Philippines early Saturday, killing at least seven people, injuring about a dozen and causing substantial damage.

Itbayat town Mayor Raul de Sagon said five people died in the first quake and two in the second, and at least 12 were injured.

“The wounded are still being brought in,” de Sagon told a local radio station, adding that he and residents were staying in the town plaza because the successive quakes damaged mostly older buildings and houses made of thick limestone.

The U.S. Geological Survey said the quakes measured 5.4 and 5.9. The Philippine seismology agency said the second quake measured 6.4.

A damage assessment team was about to be deployed when the second temblor struck and they were diverted to helping residents, de Sagon said.

Authorities were about to resume power supply when the second quake hit, prompting them to delay the resumption of electrical services, he said. More doctors may be needed if the number of injured from interior villages rises, he added.

Itbayat, part of the Batanes Islands, has a population of about 2,800 people and lies in the Luzon Strait that separates the Philippines and Taiwan.

Photos posted on Philippine media showed damaged houses and the 19th-century Santa Maria de Mayan Church in Itbayan. Residents are seen clearing debris and looking for anyone who might still be trapped.