The quake hit at a shallow depth of four kilometres near the city of Ponce and the towns of Guanica and Guayanilla, where hundreds of homes were destroyed by a quake in early January.

Last year, U.S. President Donald Trump threatened to divert disaster-recovery funds from Puerto Rico to help pay for a wall at the U.S.-Mexico border.

A magnitude 6.0 quake shook Puerto Rico on Saturday, causing further damage along the island's southern coast, where previous recent quakes have toppled homes and schools.

A 6.4-magnitude earthquake struck Puerto Rico before dawn on Tuesday, the largest in a series of quakes that have struck the U.S. territory in recent days and caused heavy damage in some areas.

It was one of the strongest quakes yet to hit the U.S. territory that has been shaking for the past week.