By DANICA COTO
Associated Press

SAN JUAN, Puerto Rico (AP) - A magnitude 5.9 quake shook Puerto Rico on Saturday, causing further damage along the island’s southern coast, where previous recent quakes have toppled homes and schools.

The U.S. Geological Survey said the 8:54 a.m. (1254 GMT) quake hit 8 miles (13 kilometers) southeast of Guanica at a shallow depth of 3 miles (5 kilometers). It was followed by several aftershocks, including a magnitude 5.2 temblor less than two minutes later.

Puerto Rico's Electric Power Authority said outages were reported across much of southern Puerto Rico and crews were assessing possible damage at power plants.

There were no immediate reports of injuries, but Deputy Mayor Elizabeth Ocasio in the southern coastal city of Ponce told The Associated Press that officials closed the city’s downtown area and two other nearby areas because of weakened infrastructure.

“One building completely collapsed,” she said. “There is a lot of historic infrastructure in Ponce."

Bárbara Cruz, a prosecutor who was in Ponce when the new quake hit, said concrete debris hit the sidewalk as buildings continued to crumble.

“Everyone is out on the street,” she said.

More landslides and damaged homes were reported, along with severe cracks on a bridge in the southwest coastal town of Guanica.

The quake, which initially had been calculated at magnitude 6.0, was the strongest shake since a magnitude 6.4 quake - the most potent to hit the island in a century - struck before dawn on Tuesday, knocking out power across Puerto Rico and leaving many without water. More than 4,000 people are in shelters, many fearful of returning to their homes, and others unable to because of extensive damage.

The director of Puerto Rico's Electric Power Authority, ordered the temporary closure of the company's largest plant, which crews had been inspecting for damage caused by earlier quakes.

The ground in southwest Puerto Rico has been shaking since Dec. 28, with more than 1,100 earthquakes, of which more than 100 were felt and more than 66 were of magnitude 3.5 or greater.

NASA reported Friday that the quakes had moved the land in parts of southern Puerto Rico as much as 5.5 inches (14 centimeters), based on satellite images before and after the temblors.

Víctor Huérfano, director of Puerto Rico’s Seismic Network, told the AP that he expects still more aftershocks as a result of the latest large one.

“It’s going to re-energize an unstable situation,” he said, adding that seismologists are studying which faults were activated. “It’s a complex zone.”

Thousands of Puerto Ricans are still without power and water, and thousands are staying in shelters and sleeping on sidewalks since Tuesday’s earthquake. That temblor killed one person, injured nine others and damaged or destroyed hundreds of homes and several schools and businesses in the island’s southwest region.