A 5.9 magnitude earthquake hit Puerto Rico on Saturday, the latest in a series of powerful tremors that have shaken the US territory in recent days, according to the US Geological Survey.

The recent tremor felt around 13 kilometres (eight miles) southeast of Guanica, a town on the island’s southern Caribbean coastline that was hard hit by earlier quakes.

The USGS revised its initial report of a 6.0 magnitude quake to 5.9.

Puerto Rico Governor Wanda Vazquez declared a state of emergency after Tuesday’s quake, which forced an automatic shutdown of the power grid.

On Tuesday, a 5.8 magnitude earthquake jolted Puerto Rico on Monday that toppled houses and caused power outages and small landslides but there were no reports of casualties.

The Pacific Tsunami Information Center in Hawaii issued a statement saying there was “no significant tsunami threat” but a small possibility of tsunami waves along coasts nearest the epicentre.

The island is still recovering from Hurricane Maria, which came ashore more than two years ago as a devastating Category 4 storm.

In December, the quake was the strongest of a series that have rippled through the island and it was followed by at least eight aftershocks.

Puerto Rico doesn’t have a public earthquake warning system, except for sirens that are supposed to ring in case of a tsunami. Residents in this neighbourhood criticized the government for what they believe is a lack of action.

One of the largest and most damaging earthquakes to hit Puerto Rico occurred in October 1918, after 7.3-magnitude quake struck near the island’s northwest coast, unleashing a tsunami and left 116 people dead.